I purchased a new pc for the express purpose to play SC2 and Civilization 5. I got the a Dell Studio with windows 7, intel core i7, 8gig ram, and the evga geforce gt 240. When playing both games the screen will randomly (some times i can get through 30mins, some times only 5mines) go black and freeze. Nothing works but a cold reboot. At first a minimizing would work, but now not even that. I've made sure my drivers were\are up to date but that's not helped. Any ideas?