Rogel

Hello all I build up a pc from scratch, the problem is it keeps crushing and freezing. I reformat and installed the OS more than twice first time was win 7 than xp. I also took all the parts off and put back again. The original power supply was 500w, now I installed a 1000w and keps crushing. the computer crash often when it runs a game like MW2 or starcraft system specifications. Graphic card: BG Tech Gforce 250 1GB Processor: Intel Quad 2.4GHz Ram: 4 Gb DDR2 Motherboard: Asus P5Q Pro Turbo Power supply: 1000 W Cooler Master Fan HDD: Seagate Barracuda 160 GB 7200 rpm. Any advice I will appreciate, I tried differents approachs and couldn't fixed