On Tuesday of last week (8-21-12) I turned on my PC like I always do. after about 10 minutes of being on and me opening up Diablo 3 my computer completely froze. nothing would respond not even Ctrl+Alt+Del. So I had to hard shut down the computer. After that a few hours later it did it again. this time I was just on internet explorer. So with me being the way I am I Reformated my computer to see if that would solve the issue. and it has not. So everyday now that I turn on my computer it seems to randomly Freeze. I have ran a windows Memory Diagnostic. I put it on Extra with Cache on and had it run 3 passes. it took about an hour and 20 min and windows found no errors or anything. I have NO idea what could be causing this. I dont wanna spend money if I can target the problem and replace the hardware thats bad. I built this computer myself and it has had NO issues since I built it and this time I cant figure it out myself. Please is there anything I can run or do to try and locate the problem? Could it be a failing power supply? the one I have in there is a 4-5 year old 1000w psu. here are my computer specs. Case - Corsair Obsidian 800D Mobo - Gigabyte X58A-UD3R CPU - Intel i7 930 2.80GHz CPU Cooler - Corsair H70 water cooler Ram - Corsair Dominator Triple channel memory 6GB Video Card - EVGA Nvidia GTX 570 superclocked PSU - Ultra X3 1000w Sound Card - Creative sound blaster X-fi Xtremegamer DvD drive - HP dvd1270 Fan controler - Lamptron FC5 Fans - 2x 120mm push-pull for H70 cpu cooler. 2x 120mm push-pull over HDD hot swap drive bay. 1x 120mm pushing air up and out case.