every game crashes

why does every game crashes on my pc?
i have an athlon 1.2 and a geforce 2 pro.
we i run a game like cs , q3 ut my screen freezes but windows , icq , cdrom don't stop playing.
i use the 12.60 drivers from nvidia.
i tried also other drivers

[qwert]

I've got an AMD 1.3 and lately I reinsatlled the system. Then I got the same probs. I downloaded the latest motherboard and chipset drivers for it and now evreything works again. Another possibilty could be, that your PC get too hot, when the graphic card and the CPU create maximum heat.
Good luck!