How to hack/change your Windows XP Boot Screen



HACKING THE XP BOOT SCREEN





This is a very simple trick to do if you have done the same for the logon screen and the start button. There are 2 ways to do this trick that I know about one is doing it manually and the other is using a program called bootxp. I am going to tell you the manual way to do it, but if you want to know the other way just let me know, so I can do an update to the guide. Now once you have downloaded your ntoskrnl.exe file save it a general location so that you will have easy access to it, like my folder.



Once you have ntoskrnl.exe file in an easy access folder, restart your pc into safe mode. Once into safe mode go to the folder where your files are located.



Now that you are there copy the file that you want to change your boot screen too. Once you have copied that file, hit the window key + r or type %windir%\system32 in the run command, so that folder as follows.



Once there paste your new file into the folder and overwrite the existing folder.



Now that you have your new file in the folder restart your pc as you normally would and your new boot screen should appear. You can download this bootscreen here.



ALWAYS BACKUP EVERYTHING YOU EDIT OR DELETE. I'M NOT RESPONSIBLE IF YOU MESS YOUR COMPUTER UP BY DOING THIS HACK OR ANY TYPE OF HACK. DO IT AT YOUR OWN RISK.

Image and ntoskrnl.exe files provided by www.themexp.org

or
u can go to

code:

http://www.overclockersclub.com/guides/hackxpbootscreen.php

Using Google for searching ebooks

Google has some fantastic potential for you to find whatever you are after on the internet.

To search for a book / program / file perhaps try the following.

Go to Google's search page and use the following criteria in the search dialog

intitle:index.of? file extension Name of item

e.g. intitle:index.of? chm syngress

This will hopefully give you a listing of all websites that google has cached that contain references to files in CHM format that are published by SYNGRESS.

---------------
I use in Google

+("index of") +("/ebooks"|"/book") +(chm|pdf|zip|rar) +syngress

or

allinurl: +(rar|chm|zip|pdf|tgz) Syngress
Enjoy

Tutorial Objective

This tutorial talks about anything about the virtual memory and how much virtual memory you need for your system.


Tutorial Introduction & Background

Today application is getting bigger and bigger. Therefore, it requires a bigger system memory in order for the system to hold the application data, instruction, and thread and to load it. The system needs to copy the application data from the HDD into the system memory in order for it to process and execute the data. Once the memory gets filled up with data, the system will stop loading the program. In this case, users need to add more memory onto their system to support that intense application. However, adding more system memory costs the money and the normal user only needs to run the the intense application that requires the memory only for one or two days. Therefore, virtual memory is introduced to solve that type of problem.


Terminology & Explanation

There are two types of memory, which are as follows:

* System Memory is a memory that is used to store the application data and instruction in order for the system to process and execute that application data and instruction. When you install the memory sticks to increase the system RAM, you are adding more system memory. System Memory can be known as either the physical memory or the main memory.

* Virtual Memory is a memory that uses a portion of HDD space as the memory to store the application data and instruction that the system deemed it doesn't need to process for now. Virtual Memory can be known as the logical memory, and it controls by the Operating System, which is Microsoft Windows. Adding the Virtual Memory can be done in system configuration.


Tutorial Information & Facts or Implementation

Virtual Memory is a HDD space that uses some portion of it as the memory. It is used to store application data and instruction that is currently not needed to be process by the system.

During the program loading process, the system will copy the application data and its instruction from the HDD into the main memory (system memory). Therefore the system can use its resources such as CPU to process and execute it. Once the system memory gets filled up, the system will start moving some of the data and instruction that don't need to process anymore into the Virtual Memory until those data and instruction need to process again. So the system can call the next application data and instruction and copy it into the main memory in order for the system to process the rest and load the program. When the data and instruction that is in the Virtual Memory needs to process again, the system will first check the main memory for its space. If there is space, it will simply swap those into the main memory. If there are not any space left for the main memory, the system will first check the main memory and move any data and instructions that doesn't need to be process into the Virtual Memory. And then swap the data and instruction that need to be process by the system from the Virtual Memory into the main memory.

Having too low of Virtual Memory size or large Virtual Memory size (meaning the size that is above double of the system memory) is not a good idea. If you set the Virtual Memory too low, then the OS will keep issuing an error message that states either Not enough memory or Virtual too low. This is because some portion of the system memory are used to store the OS Kernel, and it requires to be remain in the main memory all the time. Therefore the system needs to have a space to store the not currently needed process data and instruction when the main memory get filled up. If you set the Virtual Memory size too large to support the intensive application, it is also not a good idea. Because it will create the performance lagging, and even it will take the HDD free space. The system needs to transfer the application data and instruction back and forth between the Virtual Memory and the System Memory. Therefore, that is not a good idea. The ideal size for the Virtual Memory is the default size of Virtual Memory, and it should not be exceed the value of the triple size of system memory.

To determine how much virtual memory you need, since the user's system contains the different amount of RAM, it is based on the system. By default, the OS will set the appropriate size for Virtual Memory. The default and appropriate size of Virtual Memory is:

CODE
* 1.5 =
.

For example, if your system contains 256 MB of RAM, you should set 384 MB for Virtual Memory.

CODE
256 MB of RAM (Main Memory) * 1.5 = 384 MB for Virtual Memory


If you would like to determine how much the Virtual Memory is for your system and/or would like to configure and add more virtual memory, follow the procedure that is shown below. The following procedure is based on windows XP Professional.

1-1) Go to right-click My Computer and choose Properties

1-2) In the System Properties dialog box, go to Advanced tab

1-3) Click Settings button that is from the Performance frame

1-4) Once the Performance Options shows up on the screen, go to Advanced tab

1-5) Under the Advanced tab, click the Change button from the Virtual Memory frame to access to the Virtual Memory setting

Then the Virtual Memory dialog box appears on the screen. In there, you are able to check how much the Virtual Memory you set. If you would like to modify the size of Virtual Memory, follow the procedure that is shown below.

2-1) In there, select the drive letter that is used to install the Operating System

2-2) Choose the option that says, "Custom Size:"

Once you choose that option, the setting for Initial Size and Maximum Size become available for you to set. Initial Size (MB) means the actual size of Virtual Memory, and Maximum Size (MB) means the maximum size of Virtual Memory that is allowed to use.

Let's say if your system contains 512 MB of RAM, then the ideal setting for the Virtual Memory is as follows:

CODE

Initial Size (MB): 768
Maximum Size (MB): 1500


Once you are happy with that Virtual Memory size, click the Set button from Paging file size for selected drive to apply the setting for the Virtual Memory size. Then click the OK button to apply the setting.

That's where you can manage and configure for the size of Virtual Memory.


Additional Information

* To maintain the good overall system performance, you should be using the default size of actual size for Virtual Memory and the triple the value of the size of the main memory for the maximum size of Virtual Memory. If you find that main memory plus virtual memory is not big enough to load the intensive application, then you will need to add more main memory onto your system.


Search Keyword

virtual memory

Original Sources

CAM -
A cam is a theater rip usually done with a digital video camera. A mini tripod is sometimes used, but a lot of the time this wont be possible, so the camera make shake. Also seating placement isn't always idle, and it might be filmed from an angle. If cropped properly, this is hard to tell unless there's text on the screen, but a lot of times these are left with triangular borders on the top and bottom of the screen. Sound is taken from the onboard microphone of the camera, and especially in comedies, laughter can often be heard during the film. Due to these factors picture and sound quality are usually quite poor, but sometimes we're lucky, and the theater will be fairly empty and a fairly clear signal will be heard.



TELESYNC (TS) - A telesync is the same spec as a CAM except it uses an external audio source (most likely an audio jack in the chair for hard of hearing people). A direct audio source does not ensure a good quality audio source, as a lot of background noise can interfere. A lot of the times a telesync is filmed in an empty cinema or from the projection booth with a professional camera, giving a better picture quality. Quality ranges drastically, check the sample before downloading the full release. A high percentage of Telesyncs are CAMs that have been mislabeled.



TELECINE (TC) -
A telecine machine copies the film digitally from the reels. Sound and picture should be very good, but due to the equipment involved and cost telecines are fairly uncommon. Generally the film will be in correct aspect ratio, although 4:3 telecines have existed. A great example is the JURASSIC PARK 3 TC done last year. TC should not be confused with TimeCode , which is a visible counter on screen throughout the film.



SCREENER (SCR) -
A pre VHS tape, sent to rental stores, and various other places for promotional use. A screener is supplied on a VHS tape, and is usually in a 4:3 (full screen) a/r, although letterboxed screeners are sometimes found. The main draw back is a "ticker" (a message that scrolls past at the bottom of the screen, with the copyright and anti-copy telephone number). Also, if the tape contains any serial numbers, or any other markings that could lead to the source of the tape, these will have to be blocked, usually with a black mark over the section. This is sometimes only for a few seconds, but unfortunately on some copies this will last for the entire film, and some can be quite big. Depending on the equipment used, screener quality can range from excellent if done from a MASTER copy, to very poor if done on an old VHS recorder thru poor capture equipment on a copied tape. Most screeners are transferred to VCD, but a few attempts at SVCD have occurred, some looking better than others.



DVD-SCREENER (DVDscr) -Same premise as a screener, but transferred off a DVD. Usually letterbox , but without the extras that a DVD retail would contain. The ticker is not usually in the black bars, and will disrupt the viewing. If the ripper has any skill, a DVDscr should be very good. Usually transferred to SVCD or DivX/XviD.



DVDRip - A copy of the final released DVD. If possible this is released PRE retail (for example, Star Wars episode 2) again, should be excellent quality. DVDrips are released in SVCD and DivX/XviD.



VHSRip -Transferred off a retail VHS, mainly skating/sports videos and XXX releases.



TVRip -TV episode that is either from Network (capped using digital cable/satellite boxes are preferable) or PRE-AIR from satellite feeds sending the program around to networks a few days earlier (do not contain "dogs" but sometimes have flickers etc) Some programs such as WWF Raw Is War contain extra parts, and the "dark matches" and camera/commentary tests are included on the rips. PDTV is capped from a digital TV PCI card, generally giving the best results, and groups tend to release in SVCD for these. VCD/SVCD/DivX/XviD rips are all supported by the TV scene.



WORKPRINT (WP) -A workprint is a copy of the film that has not been finished. It can be missing scenes, music, and quality can range from excellent to very poor. Some WPs are very different from the final print (Men In Black is missing all the aliens, and has actors in their places) and others can contain extra scenes (Jay and Silent Bob) . WPs can be nice additions to the collection once a good quality final has been obtained.



DivX Re-Enc -A DivX re-enc is a film that has been taken from its original VCD source, and re-encoded into a small DivX file. Most commonly found on file sharers, these are usually labeled something like Film.Name.Group(1of2) etc. Common groups are SMR and TND. These aren't really worth downloading, unless you're that unsure about a film u only want a 200mb copy of it. Generally avoid.



Watermarks -
A lot of films come from Asian Silvers/PDVD (see below) and these are tagged by the people responsible. Usually with a letter/initials or a little logo, generally in one of the corners. Most famous are the "Z" "A" and "Globe" watermarks.



Asian Silvers / PDVD -
These are films put out by eastern bootleggers, and these are usually bought by some groups to put out as their own. Silvers are very cheap and easily available in a lot of countries, and its easy to put out a release, which is why there are so many in the scene at the moment, mainly from smaller groups who don't last more than a few releases. PDVDs are the same thing pressed onto a DVD. They have removable subtitles, and the quality is usually better than the silvers. These are ripped like a normal DVD, but usually released as VCD.






Formats

VCD -
VCD is an mpeg1 based format, with a constant bitrate of 1150kbit at a resolution of 352x240 (NTCS). VCDs are generally used for lower quality transfers (CAM/TS/TC/Screener(VHS)/TVrip(analogue) in order to make smaller file sizes, and fit as much on a single disc as possible. Both VCDs and SVCDs are timed in minutes, rather than MB, so when looking at an mpeg, it may appear larger than the disc capacity, and in reality u can fit 74min on a CDR74.



SVCD -
SVCD is an mpeg2 based (same as DVD) which allows variable bit-rates of up to 2500kbits at a resolution of 480x480 (NTSC) which is then decompressed into a 4:3 aspect ratio when played back. Due to the variable bit-rate, the length you can fit on a single CDR is not fixed, but generally between 35-60 Mins are the most common. To get a better SVCD encode using variable bit-rates, it is important to use multiple "passes". this takes a lot longer, but the results are far clearer.



XVCD/XSVCD -
These are basically VCD/SVCD that don't obey the "rules". They are both capable of much higher resolutions and bit-rates, but it all depends on the player to whether the disc can be played. X(S)VCD are total non-standards, and are usually for home-ripping by people who don't intend to release them.



KVCD Thanks for lardo4life for the info
KVCD is a modification to the standard MPEG-1 and MPEG-2 GOP structure and Quantization Matrix. It enables you to create over 120 minutes of near DVD quality video, depending on your material, on a single 80 minute CD-R/CD-RW. We have published these specifications as KVCDx3, our official resolution, which produce 528x480 (NTSC) and 528x576 (PAL) MPEG-1 variable bit rate video, from 64Kbps to 3,000Kbps. Using a resolution of 352x240 (NTSC) or 352x288 (PAL), it's possible to encode video up to ~360 minutes of near VCD quality on a single 80 minute CD-R. The mpeg files created will play back in most modern standalone DVD players. You must burn the KVCD MPEG files as non-standard VCD or non-standard SVCD (depends on your player) with Nero or VCDEasy.



DivX / XviD -
DivX is a format designed for multimedia platforms. It uses two codecs, one low motion, one high motion. most older films were encoded in low motion only, and they have problems with high motion too. A method known as SBC (Smart Bit-rate Control) was developed which switches codecs at the encoding stage, making a much better print. The format is Ana orphic and the bit-rate/resolution are interchangeable. Due to the higher processing power required, and the different codecs for playback, its unlikely we'll see a DVD player capable of play DivX for quite a while, if at all. There have been players in development which are supposedly capable, but nothing has ever arisen. The majority of PROPER DivX rips (not Re-Encs) are taken from DVDs, and generally up to 2hours in good quality is possible per disc. Various codecs exist, most popular being the original Divx3.11a and the new XviD codecs.



CVD -
CVD is a combination of VCD and SVCD formats, and is generally supported by a majority of DVD players. It supports MPEG2 bit-rates of SVCD, but uses a resolution of 352x480(ntsc) as the horizontal resolution is generally less important. Currently no groups release in CVD.



DVD-R -
Is the recordable DVD solution that seems to be the most popular (out of DVD-RAM, DVD-R and DVD+R). it holds 4.7gb of data per side, and double sided discs are available, so discs can hold nearly 10gb in some circumstances. SVCD mpeg2 images must be converted before they can be burnt to DVD-R and played successfully. DVD>DVDR copies are possible, but sometimes extras/languages have to be removed to stick within the available 4.7gb.



MiniDVD -
MiniDVD/cDVD is the same format as DVD but on a standard CDR/CDRW. Because of the high resolution/bit-rates, its only possible to fit about 18-21 mins of footage per disc, and the format is only compatible with a few players.






Misc Info

Regional Coding -
This was designed to stop people buying American DVDs and watching them earlier in other countries, or for older films where world distribution is handled by different companies. A lot of players can either be hacked with a chip, or via a remote to disable this.



RCE -
RCE (Regional Coding Enhancement) was designed to overcome "Multiregion" players, but it had a lot of faults and was overcome. Very few titles are RCE encoded now, and it was very unpopular.



Macrovision -
Macrovision is the copy protection employed on most commercial DVDs. Its a system that will display lines and darken the images of copies that are made by sending the VHS signals it can't understand. Certain DVD players (for example the Dansai 852 from Tescos) have a secret menu where you can disable the macrovision, or a "video stabaliser" costs about 30UKP from Maplin (www.maplin.co.uk)



NTSC/PAL -
NTSC and PAL are the two main standards used across the world. NTSC has a higher frame rate than pal (29fps compared to 25fps) but PAL has an increased resolution, and gives off a generally sharper picture. Playing NTSC discs on PAL systems seems a lot easier than vice-versa, which is good news for the Brits An RGB enabled scart lead will play an NTSC picture in full colour on most modern tv sets, but to record this to a VHS tape, you will need to convert it to PAL50 (not PAL60 as the majority of DVD players do.) This is either achieved by an expensive converter box (in the regions of £200+) an onboard converter (such as the Dansai 852 / certain Daewoos / Samsung 709 ) or using a World Standards VCR which can record in any format.



News Sites -
There are generally 2 news sites for film release for p2p and they are:

nforce - VCD Help
Code:
http://www.vcdhelp.com/

Code:
http://www.nforce.nl.




About Release Files

RARset -
The movies are all supplied in RAR form, whether its v2 (rar>.rxx) or v3 (part01.rar > partxx.rar) form.



BIN/CUE -
VCD and SVCD films will extract to give a BIN/CUE. Load the .CUE into notepad and make sure the first line contains only a filename, and no path information. Then load the cue into Nero/CDRWin etc and this will burn the VCD/SVCD correctly. TV rips are released as MPEG. DivX files are just the plain DivX - .AVI



NFO -
An NFO file is supplied with each movie to promote the group, and give general iNFOrmation about the release, such as format, source, size, and any notes that may be of use. They are also used to recruit members and acquire hardware for the group.

SFV -
Also supplied for each disc is an SFV file. These are mainly used on site level to check each file has been uploaded correctly, but are also handy for people downloading to check they have all the files, and the CRC is correct. A program such as pdSFV or hkSFV is required to use these files.






Usenet Information

Access -
To get onto newsgroups, you will need a news server. Most ISPs supply one, but this is usually of poor retention (the amount of time the files are on server for) and poor completition (the amount of files that make it there). For the best service, a premium news server should be paid for, and these will often have bandwidth restrictions in place.



Software -
You will need a newsreader to access the files in the binary newsgroups. There are many different readers, and its usually down to personal opinion which is best. Xnews / Forte Agent / BNR 1 / BNR 2 are amongst the popular choices. Outlook has the ability to read newsgroups, but its recommended to not use that.



Format -
Usenet posts are often the same as those listed on VCDQUALiTY (i.e., untouched group releases) but you have to check the filenames and the description to make sure you get what you think you are getting. Generally releases should come down in .RAR sets. Posts will usually take more than one day to be uploaded, and can be spread out as far as a week.



PAR files -
As well as the .rxx files, you will also see files listed as .pxx/.par . These are PARITY files. Parity files are common in usenet posts, as a lot of times, there will be at least one or two damaged files on some servers. A parity file can be used to replace ANY ONE file that is missing from the rar set. The more PAR files you have, the more files you can replace. You will need a program called SMARTPAR for this.






Scene Tags

PROPER -
Due to scene rules, whoever releases the first Telesync has won that race (for example). But if the quality of that release is fairly poor, if another group has another telesync (or the same source in higher quality) then the tag PROPER is added to the folder to avoid being duped. PROPER is the most subjective tag in the scene, and a lot of people will generally argue whether the PROPER is better than the original release. A lot of groups release PROPERS just out of desperation due to losing the race. A reason for the PROPER should always be included in the NFO.



SUBBED -
In the case of a VCD, if a release is subbed, it usually means it has hard encoded subtitles burnt throughout the movie. These are generally in malaysian/chinese/thai etc, and sometimes there are two different languages, which can take up quite a large amount of the screen. SVCD supports switch able subtitles, so some DVDRips are released with switch able subs. This will be mentioned in the NFO file if included.



UNSUBBED -
When a film has had a subbed release in the past, an Unsubbed release may be released

LIMITED -
A limited movie means it has had a limited theater run, generally opening in less than 250 theaters, generally smaller films (such as art house films) are released as limited.



INTERNAL -
An internal release is done for several reasons. Classic DVD groups do a lot of .INTERNAL. releases, as they wont be dupe'd on it. Also lower quality theater rips are done INTERNAL so not to lower the reputation of the group, or due to the amount of rips done already. An INTERNAL release is available as normal on the groups affiliate sites, but they can't be traded to other sites without request from the site ops. Some INTERNAL releases still trickle down to IRC/Newsgroups, it usually depends on the title and the popularity. Earlier in the year people referred to Centropy going "internal". This meant the group were only releasing the movies to their members and site ops. This is in a different context to the usual definition.



STV -
Straight To Video. Was never released in theaters, and therefore a lot of sites do not allow these.



OTHER TAGS -

*WS* for widescreen (letterbox)
*FS* for Fullscreen.



RECODE -
A recode is a previously released version, usually filtered through TMPGenc to remove subtitles, fix color etc. Whilst they can look better, its not looked upon highly as groups are expected to obtain their own sources.



REPACK -
If a group releases a bad rip, they will release a Repack which will fix the problems.



NUKED -
A film can be nuked for various reasons. Individual sites will nuke for breaking their rules (such as "No Telesyncs") but if the film has something extremely wrong with it (no soundtrack for 20mins, CD2 is incorrect film/game etc) then a global nuke will occur, and people trading it across sites will lose their credits. Nuked films can still reach other sources such as p2p/usenet, but its a good idea to check why it was nuked first in case. If a group realise there is something wrong, they can request a nuke.

NUKE REASONS :: this is a list of common reasons a film can be nuked for (generally DVDRip)

** BAD A/R ** :: bad aspect ratio, ie people appear too fat/thin
** BAD IVTC ** :: bad inverse telecine. process of converting framerates was incorrect.
** INTERLACED ** :: black lines on movement as the field order is incorrect.



DUPE -
Dupe is quite simply, if something exists already, then theres no reason for it to exist again without proper reason.

Fatal error: the system has become unstable or is busy," it says. "Enter to return to Windows or press Control-Alt-Delete to restart your computer. If you do this you will lose any unsaved information in all open applications."

You have just been struck by the Blue Screen of Death. Anyone who uses Mcft Windows will be familiar with this. What can you do? More importantly, how can you prevent it happening?

1 Hardware conflict

The number one reason why Windows crashes is hardware conflict. Each hardware device communicates to other devices through an interrupt request channel (IRQ). These are supposed to be unique for each device.

For example, a printer usually connects internally on IRQ 7. The keyboard usually uses IRQ 1 and the floppy disk drive IRQ 6. Each device will try to hog a single IRQ for itself.

If there are a lot of devices, or if they are not installed properly, two of them may end up sharing the same IRQ number. When the user tries to use both devices at the same time, a crash can happen. The way to check if your computer has a hardware conflict is through the following route:

* Start-Settings-Control Panel-System-Device Manager.

Often if a device has a problem a yellow '!' appears next to its description in the Device Manager. Highlight Computer (in the Device Manager) and press Properties to see the IRQ numbers used by your computer. If the IRQ number appears twice, two devices may be using it.

Sometimes a device might share an IRQ with something described as 'IRQ holder for PCI steering'. This can be ignored. The best way to fix this problem is to remove the problem device and reinstall it.

Sometimes you may have to find more recent drivers on the internet to make the device function properly. A good resource is www.driverguide.com. If the device is a soundcard, or a modem, it can often be fixed by moving it to a different slot on the motherboard (be careful about opening your computer, as you may void the warranty).

When working inside a computer you should switch it off, unplug the mains lead and touch an unpainted metal surface to discharge any static electricity.

To be fair to Mcft, the problem with IRQ numbers is not of its making. It is a legacy problem going back to the first PC designs using the IBM 8086 chip. Initially there were only eight IRQs. Today there are 16 IRQs in a PC. It is easy to run out of them. There are plans to increase the number of IRQs in future designs.

2 Bad Ram

Ram (random-access memory) problems might bring on the blue screen of death with a message saying Fatal Exception Error. A fatal error indicates a serious hardware problem. Sometimes it may mean a part is damaged and will need replacing.

But a fatal error caused by Ram might be caused by a mismatch of chips. For example, mixing 70-nanosecond (70ns) Ram with 60ns Ram will usually force the computer to run all the Ram at the slower speed. This will often crash the machine if the Ram is overworked.

One way around this problem is to enter the BIOS settings and increase the wait state of the Ram. This can make it more stable. Another way to troubleshoot a suspected Ram problem is to rearrange the Ram chips on the motherboard, or take some of them out. Then try to repeat the circumstances that caused the crash. When handling Ram try not to touch the gold connections, as they can be easily damaged.

Parity error messages also refer to Ram. Modern Ram chips are either parity (ECC) or non parity (non-ECC). It is best not to mix the two types, as this can be a cause of trouble.

EMM386 error messages refer to memory problems but may not be connected to bad Ram. This may be due to free memory problems often linked to old Dos-based programmes.

3 BIOS settings

Every motherboard is supplied with a range of chipset settings that are decided in the factory. A common way to access these settings is to press the F2 or delete button during the first few seconds of a boot-up.

Once inside the BIOS, great care should be taken. It is a good idea to write down on a piece of paper all the settings that appear on the screen. That way, if you change something and the computer becomes more unstable, you will know what settings to revert to.

A common BIOS error concerns the CAS latency. This refers to the Ram. Older EDO (extended data out) Ram has a CAS latency of 3. Newer SDRam has a CAS latency of 2. Setting the wrong figure can cause the Ram to lock up and freeze the computer's display.

Mcft Windows is better at allocating IRQ numbers than any BIOS. If possible set the IRQ numbers to Auto in the BIOS. This will allow Windows to allocate the IRQ numbers (make sure the BIOS setting for Plug and Play OS is switched to 'yes' to allow Windows to do this.).

4 Hard disk drives

After a few weeks, the information on a hard disk drive starts to become piecemeal or fragmented. It is a good idea to defragment the hard disk every week or so, to prevent the disk from causing a screen freeze. Go to

* Start-Programs-Accessories-System Tools-Disk Defragmenter

This will start the procedure. You will be unable to write data to the hard drive (to save it) while the disk is defragmenting, so it is a good idea to schedule the procedure for a period of inactivity using the Task Scheduler.

The Task Scheduler should be one of the small icons on the bottom right of the Windows opening page (the desktop).

Some lockups and screen freezes caused by hard disk problems can be solved by reducing the read-ahead optimisation. This can be adjusted by going to

* Start-Settings-Control Panel-System Icon-Performance-File System-Hard Disk.

Hard disks will slow down and crash if they are too full. Do some housekeeping on your hard drive every few months and free some space on it. Open the Windows folder on the C drive and find the Temporary Internet Files folder. Deleting the contents (not the folder) can free a lot of space.

Empty the Recycle Bin every week to free more space. Hard disk drives should be scanned every week for errors or bad sectors. Go to

* Start-Programs-Accessories-System Tools-ScanDisk

Otherwise assign the Task Scheduler to perform this operation at night when the computer is not in use.

5 Fatal OE exceptions and VXD errors

Fatal OE exception errors and VXD errors are often caused by video card problems.

These can often be resolved easily by reducing the resolution of the video display. Go to

* Start-Settings-Control Panel-Display-Settings

Here you should slide the screen area bar to the left. Take a look at the colour settings on the left of that window. For most desktops, high colour 16-bit depth is adequate.

If the screen freezes or you experience system lockups it might be due to the video card. Make sure it does not have a hardware conflict. Go to

* Start-Settings-Control Panel-System-Device Manager

Here, select the + beside Display Adapter. A line of text describing your video card should appear. Select it (make it blue) and press properties. Then select Resources and select each line in the window. Look for a message that says No Conflicts.

If you have video card hardware conflict, you will see it here. Be careful at this point and make a note of everything you do in case you make things worse.

The way to resolve a hardware conflict is to uncheck the Use Automatic Settings box and hit the Change Settings button. You are searching for a setting that will display a No Conflicts message.

Another useful way to resolve video problems is to go to

* Start-Settings-Control Panel-System-Performance-Graphics

Here you should move the Hardware Acceleration slider to the left. As ever, the most common cause of problems relating to graphics cards is old or faulty drivers (a driver is a small piece of software used by a computer to communicate with a device).

Look up your video card's manufacturer on the internet and search for the most recent drivers for it.

6 Viruses

Often the first sign of a virus infection is instability. Some viruses erase the boot sector of a hard drive, making it impossible to start. This is why it is a good idea to create a Windows start-up disk. Go to

* Start-Settings-Control Panel-Add/Remove Programs

Here, look for the Start Up Disk tab. Virus protection requires constant vigilance.

A virus scanner requires a list of virus signatures in order to be able to identify viruses. These signatures are stored in a DAT file. DAT files should be updated weekly from the website of your antivirus software manufacturer.

An excellent antivirus programme is McAfee VirusScan by Network Associates ( www.nai.com). Another is Norton AntiVirus 2000, made by Symantec ( www.symantec.com).

7 Printers

The action of sending a document to print creates a bigger file, often called a postscript file.

Printers have only a small amount of memory, called a buffer. This can be easily overloaded. Printing a document also uses a considerable amount of CPU power. This will also slow down the computer's performance.

If the printer is trying to print unusual characters, these might not be recognised, and can crash the computer. Sometimes printers will not recover from a crash because of confusion in the buffer. A good way to clear the buffer is to unplug the printer for ten seconds. Booting up from a powerless state, also called a cold boot, will restore the printer's default settings and you may be able to carry on.

8 Software

A common cause of computer crash is faulty or badly-installed software. Often the problem can be cured by uninstalling the software and then reinstalling it. Use Norton Uninstall or Uninstall Shield to remove an application from your system properly. This will also remove references to the programme in the System Registry and leaves the way clear for a completely fresh copy.

The System Registry can be corrupted by old references to obsolete software that you thought was uninstalled. Use Reg Cleaner by Jouni Vuorio to clean up the System Registry and remove obsolete entries. It works on Windows 95, Windows 98, Windows 98 SE (Second Edition), Windows Millennium Edition (ME), NT4 and Windows 2000.

Read the instructions and use it carefully so you don't do permanent damage to the Registry. If the Registry is damaged you will have to reinstall your operating system. Reg Cleaner can be obtained from www.jv16.org

Often a Windows problem can be resolved by entering Safe Mode. This can be done during start-up. When you see the message "Starting Windows" press F4. This should take you into Safe Mode.

Safe Mode loads a minimum of drivers. It allows you to find and fix problems that prevent Windows from loading properly.

Sometimes installing Windows is difficult because of unsuitable BIOS settings. If you keep getting SUWIN error messages (Windows setup) during the Windows installation, then try entering the BIOS and disabling the CPU internal cache. Try to disable the Level 2 (L2) cache if that doesn't work.

Remember to restore all the BIOS settings back to their former settings following installation.

9 Overheating

Central processing units (CPUs) are usually equipped with fans to keep them cool. If the fan fails or if the CPU gets old it may start to overheat and generate a particular kind of error called a kernel error. This is a common problem in chips that have been overclocked to operate at higher speeds than they are supposed to.

One remedy is to get a bigger better fan and install it on top of the CPU. Specialist cooling fans/heatsinks are available from www.computernerd.com or www.coolit.com

CPU problems can often be fixed by disabling the CPU internal cache in the BIOS. This will make the machine run more slowly, but it should also be more stable.

10 Power supply problems

With all the new construction going on around the country the steady supply of electricity has become disrupted. A power surge or spike can crash a computer as easily as a power cut.

If this has become a nuisance for you then consider buying a uninterrupted power supply (UPS). This will give you a clean power supply when there is electricity, and it will give you a few minutes to perform a controlled shutdown in case of a power cut.

It is a good investment if your data are critical, because a power cut will cause any unsaved data to be lost.