I would say its the card over heating but its so damn random. I can play for hours and its fine and some times i can just turn on my computer and it locks up and restarts 5 minutes into a game. Had this happen on crysis a few times, COD a bunch and World of Warcraft once. I got a core 2 duo 2.66 with 2 gigs running 8800gxt on vista home premium 64 I have no idea whats really causing the error because the screen goes black and loses signal. The sound is still in the background like the game is still playing but after a few moments it locks up and then windows restarts itself. could this just be driver related?