Computer resets randomly?

Hello people better than me with computers!

Here's the problem. I noticed a game I was playing was running like shit. It's been running fine for years. In a fit of "i dunno lol" I installed new video card drivers.

Now instead of running like shit, my computer resets itsself every so often when it feels like it, but it only seems to happen when I have a 3D game running.

My google-fu is weak, but most of the topics on the matter talk about either a virus(Sasser, scanned and not detected) or overheating problems (It's fucking winter, and my computer is running at ~45 degrees most of the time). I opened up the box and cleaned out the fan and all that just to be sure, and made sure everything was connected tightly.

I'm using Windows XP, and my Graphics card is a GeForce 6600 (lol). I'm sorry if this isn't alot of information, I can contribute more. Just not sure what is relevant.

>>1

　　　　　　　　     ∧＿∧　　　／￣￣￣￣￣￣￣￣
　　　　　　　　　 （　´∀｀）　＜　you have a serious hardware compatibility there mah boii , i sugest you just unplug the card try to see if it lets you go in with the normal motherboard card , i have a similar issue long time ago with and aladin pro video card when switching from w98 to xp ,the card was incompatible with xp so maybe thats your case
　　　　　　　　／　　　　|　　　 ＼＿＿＿＿＿＿＿＿
　　　　　　　/ 　　　 　 .|　　　　　
　　　　　　 / "⌒ヽ |.ｲ |
　　　＿＿ |　　　.ノ | || |＿＿
　 .　　　 ノく＿＿つ∪∪　　 ＼
　　　＿（（＿＿＿＿＿＿＿＿_＼
　　 ￣￣ヽつ￣￣￣￣￣￣ | |￣
　　　＿＿＿＿＿＿＿＿＿__| |
　　 ￣￣￣￣￣￣￣￣￣￣| |