I assume you also disabled vsync, and therefore you got no frame limiter in place. COH2 is one hell of a stress test on it's own sadly.
Nevertheless, your PC should never do a hard reset due a game in the first place. That smells like faulty drivers or hardware issues - i didn't suggest the mentioned above for no reason.
Yes, vsync is disabled.
I concur - a game should never be able to get deep enough into the guts of the OS to cause a hard reset. However, that is the situation with which I'm faced. I don't believe that the card is to blame as it has worked well with every application *except* COH2. I tried drivers from 3 different sources (nVidia, Microsoft, and Asus) and got the exact same result every time. It even crashes at the exact same point in the performance test - the instant that the SU-76 takes a hit, the computer crashes. I tried playing a solo game, and it lasted about 15 seconds before it too crashed hard. I dumbed down the settings in COH2 to their lowest possible value in every category, got the same result. I let the game run its analysis and choose the settings it felt were appropriate, got the same result. I tried maxing them out, got the same result. I'm quite frustrated. In all the time I've been gaming, this is the first time I've ever posted to a forum looking for guidance.