Blue screen (not OD) random video game crash

Let me start off saying this doesn't happen with halo and guild wars
This DOES however happen when I play most games downloaded from the net, including maple story, gunz, knight online, and shaiya.

What happens is, is that the game will run fine for a few minutes, then the screen will flicker a bit, then my computer reboots itself.
The screen turns blue before rebooting, but no text appears. After I log back onto windows and look at the error web page it lists it as a driver error.
I have used many versions of the ATI drivers for my card, and used the CCC and just used the drivers. Nothing seems to fix this problem.

What can I do?
Thank you very much for any replies!