Computer freezes on some games

[RustyPwns!]

So yeah my computer freezes all the time when I play most games. My computer almost never crashes on bfbc2 and rarely crashes on starcraft II but all the time on dead space 2, apb, and sometimes black ops. What happens is my screen turns black and an audio loop studder sound occurs and then my computer turns off. It started when I installed my 460's SLI and my computer wouldn't even turn on at first when I then discovered it was crappy 266.58 drivers, and now my computer sometimes crashes on 270. Could it be a hardware problem? My computer doesn't really overheat at all...

sidenote; computer never crashes on desktop, only on games.

[ame]https://rapidshare.com/files/458908607/DxDiag.txt[/ame]

 

[RustyPwns!]

Gee thanks for the help guys -_________-

 

[Ric]

Let me remind you, this is a free-of-charge technical sub forum and most of the certified real life technicians help people for free on these forums.

Would you be willing to do a video card stress test for me?
Download this, install it, and run it. Report back to us the various results from the stress tests.