Windows

THis sounds like a hardware issue or corrupted system files.

FIRST THINGS FIRST
You need to find the error message received on crash. Windows XP is set to simply reboot on system failure and therefore you don't get a STOP error code to resolve.

To turn off the automatic reboot on system error,
Control Panel>system>advanced>startup & recovery settings, uncheck the box to
reboot on system failure.
The next time it happens, you should get an
error message rather than reboot.

When you get the error message you can post it back here or also you can search for answers instantly on http://www.deja.com by searching for the first part or the STOP error code or search for the same on Microsoft's Knowedgebase.

I have seen this problem a number of times, and in most of those cases it was bad memory. If you have access to another memory module, remove the memory in the system and try a different module. If you have more than one module, try removing all but one and see if the problem occurs with one but not with the others.

Also, there are memory tests available that can run from a self booting floppy. You can try one of those without having to boot to windows.

One other thing, you might want to check the capacitors on your board. If any look swelled or if any appear to be leaking (black gooey stuff) you might want to check with your MB manufacturer about a replacement. This has been a problem on many boards and can manifest a number of problems.

The error that is brought up is "DRIVER_IRQL_NOT_LESS_OR_EQUAL"

***STOP: 0x000000D1 (0x00000102, 0x00000002, 0x00000001, 0xF81BCD6a0
*** ar5211.sys - Address F81BCD6A base at F818E000, Date Stamp 3E7AAB83

I believe that my wireless lan card is causing this problem. When I remove this card the system stops rebooting. I have uninstalled and reinstalled the card but it still causes problems. Is it more likely to be a hardware or software problem with the card? How can I complerelty remove all traces of drivers and hardware information from the system for this card? When I uninstall and reinstall, the system names the card the same thing with the addition of a #2, #3, #4 for however many times you have reinstalled it. Let me know how I can wipe this clean and start anew.

As far as the PC "remembering" the wireless card, don't just uninstall the card, also uninstall the entire TCP/IP stack.

You're not really uninstalling the TCP/IP stack, you're really just rebuilding it...it's virtually impossible to truly uninstall something as essential to your PC for example, in XP.

But that should get rid of the Wireless card #1, #2, #3, etc.