I recently upgraded from windows 98 to XP and ever since then I haven't been able to play any of my games. I play for a few minutes and then the game either crashes back to my desktop or restarts my computer entirely.

Specs:
-AMD Athlon XP 2400+
-ATI Radeon 9000 128mb
-Windows XP Pro SP2
-512mb ddr ram

My video driver and directX are fully updated, somebody please help me!

Please list the games and also the details of the crash such as the exact error message. Check the event viewer.

The games are just any game I try to play:
-Doom 3
-Splinter Cell Chaos Theory
-Halo
-Jedi Academy
-Diablo 2
-Diablo
-Warcraft III
-Half Life 2
-Empire Earth
-Starcraft
-UT 2004
...the list goes on

I will post later when I find the error message.

Games are one of the most taxing applications for a computer so naturally the CPU, video card, and PSU are going to get significantly hotter during gaming.

I feel guilty suggesting this since I'm repeating what I've read several times from another TS member that posts in these forums, but:

open the side of your computer's case and blow a fan directly at the open computer while you play the games to see if it still crashes. If it doesn't crash, heat is your problem.

I believe the "copyright" for that belongs to realblackstuff : ) Possibly another wise TS member.

buy a faster fan for yer cpu!
more air!

Usually opening the case and blowing a fan on it isnt a good idea (or opening the case at all). Any Aplus tech will tell you. It can cause dust to blow into areas of your motherboard that arent visible, which will cause the dust to gather and act as an insulator. I guess its alright if you're doing it for a short amount of time, but for long periods...............no! Plus blowing a fan on your components wont significantly drop your CPU temp, since the heatsink is in close contact with the processor, you'd have to have the fan in direct contact with the CPU heatsink and have the case closed at the same time to promote proper heat dissipation and heatsink cooling via the cycling of air in your case. I dont think this is a CPU issue. I think it's more or less a BIOS issue. I'd try updating your bios first. Try it, see if it still crashes. Alot of older comps have outdated BIOS.