|Ok, then I'd reccomend getting a hold of the manual for your motherboard, or searching online to find instructions for your BIOS. AGP Aperture Size is a setting I believe can sometimes (usually system slowdowns/instability) cause problems if incorrect. Fast Write, or any shadowing can often cause problems. Incorrect AGP mhz speed can mess things up if that's wrong. Make sure it's on Auto, or if that option isn't available, try to find out what your card supports. I often find it's around 66mhz (AGP3.0 8x), but don't take my word for it.|
If it were me, I'd think about reinstalling Windows with the vague idea that somewhere along the lines, human error has caused a driver mixup and it's just messing with the OS hardware configuration.
You could try system restore points as far back as possible, if you get lucky then go with it, if not then undo the restore.
Another idea, might be to check that it is actually the graphics card. Also, I don't know if anyone has mentioned it, but a classic diagnosis is MSCONFIG from the run command, found on the start menu. Temporaraly disable the appropriate areas until you come accross a clue.
Um, and lastly, the final thing I can think of at the moment, if I was in your situation, would be to check from Safe Mode that ALL old (and unused) drivers are REMOVED as that is a number ONE cause for problems with hardware.
I recently went from an nVidia GeForce 6600LE card to an ATI Radeon X800 Pro/GTO card. I was so busy building the computer and concentrating on the hardware, that I forgot to actually remove the old drivers, not a move I usually make. I got rid of the old ones, but I found that two nVidia based programs where loading up after logging in to Windows XP. nVidia graphics card users will be familiar with the programs. So, I removed these and it solved a random crash similar to yours. It also sped the graphics up somewhat.
Keep posting, and I'll let you know if I end up with anymore ideas. haha. Good luck, fellow computer user. =)
(make sure you've exhasted other options before reinstalling, it's better to know what the problem IS rather than just burrying the evidence and forgetting about it, so you can better defend yourself against these issues in the future)
...It is simply phsychological analysis consisting mostly of theories I myself have to decypher and deter their respective plausibility...