Ok, I really need your help people. For quite some time my PC crashes when playing video games. When i play games like Half Life 2(and episodes), TF2, Portal, COD4, CS:S everything runs fine. When i play games like Crysis, GTA 4, STALKER:Clear Sky, Bioshock(not windowed mode) my PC crashed after 5-10 minutes and it's been bothering me since i really want to play those games. The weird thing is that GTA 4 doesn't crash if i have all the settings maxed out. It's similar with Crysis too: the higher the settings are the longer it takes for the game to crash. So i play the games and after a short time the screen goes black with a little green line going horizontally across the screen for half of the second and then the screen shows as if the PC is turned of the little analog/digital sign(as the samsung monitors usually do when no signal). The sound loops like when i get a bsod, and i have to restart my computer manually. So I've figure that it's not a hardware problem maybe(since it would crashed sooner under higher settings because of overheating or something similar). My rig: Intel Core Duo E8500 2x3.17GHz (no oc.) DFI Lan Party DK P45-T2RS 4GB DDR2 800MHz Mushkin Value Series ATI Radeon HD4850 Toxic 512MB HDD WD Caviar 640GB (didn't make partitions) Mon. Samsung 20'' on Windows Vista Ultimate x86 with SP1=>DX 10 (or 10.1 not sure) I already tried to google it but i had no luck. I'm ready for cooperation. If someone could help me i would be very very grateful.