Recently i bought xfx gtx275,replacing my old xfx 8800gt-alpha dog.Problem is,while playing cod5,dragon age,some other games;my system just stop working in the middle of the game.It just happening again and again.I also installed latest driver,used riva-tuner for optimized the fan speed(not for over clocking),even tried after fresh installation of xp but can't fix this problem.My system: cpu-E8200@3.6Ghz,4gb ddr2 axe-ram,500gb hdd,P5K-vm mobo,thermaltake toughpower 650 watt,20" samsung lcd.I didn't face this kind of problems with my old 8800gt.Need some help?