Random lockups

Right well i have been having problems with my computer suffering random lockups it can sometimes last 2 days as it did today then suddenly lockup usually during far cry, when using azureus or switched user. I suspected it was video card as it happend after i reinstalled graphics driver so i used driver cleaner and installed omega drivers. I then found that i had unplugged my extractor fan under the graphics card and the heatsink was hot so i plugged it back in and no problems and that was sunday and now i am suffering it again any advice will be greatly appreciated btw i am not overclocked yet

Games tend to push a system really hard. I'd look for heat issues. If not that, then try running memtest.

ok

right well it doesnt happen just during games the computer can be idle i ran an in windows mem test and had no errors ill do a more in depth one tommorow but it had no errors i do touch heat sinks wen it crashes so i can check is there anything else i should try i have check system logs and theres nothing

Install something that monitors your temps and see how high they are going.

right

ok i installed asus probe and had it check while i was away and at the timne it froze it showed that the temps were normal. today i tried to play half life on my pc and got a memory error and then comp crapped out so i decided to try switching ram slots and i got the cpu overclocking asus voice message which is strange as i have no overclock and refused to show an image.i then changed ram slots back and was fine so what are your thoughts?

ok right

flashed bios to latest version and that solved the ram problem so i can put it in other slot i still get the error with half life 2 i ran memtest for 2 hours with 4 passes and no erors i dont think i am having heat issues any other ideas?