Something strange is happening...Follow

Hey everyone, i've been experiencing some problems with almost all of my games lately. Around four days ago, my computer started crashing unexpectedly on all the games that I play. It takes all of maybe 30 seconds for the whole computer (not just the game) to crash when a game is booted up.

When the computer crashes, the screen either goes black and or it stays on the last frame before it crashes. It also repeats the last sound it was playing before the crash until i manually power down the computer. Using the keyboard does nothing. I can Alt+F4, Ctrl+Alt+Del, Win-key+Reboot all i want, nothing happens.

The thing i find is that it happens to my larger games. Half Life: 2 and Counter-Strike Source, WoW, SWG, and UT2004. It hasn't crashed yet when i play Starcraft.

Well, i'm wondering if anyone can help me. I'm gameless at this point and i'm looking for some direction. My computer specs are: AMD Athlon 64 3200+ (2.01 GHz), 1 GB of RAM, and a GeForce 6600 GT. Please respond if you have any input.

I have an internal thermostat that reads out the temperatures to be mid-90's. My case looks to be pretty clean in terms of dust. I'll double-check really quick. Thanks for the info.