Hi saw this thread and it prompted me to join the forums, since this seems a pretty common problem.
First had this problem with XP 64bit, when i left it idle it froze and had no choice but to use the reset button on my case. Looked everywhere and tried everything that has been mentioned here; updated drivers
, power management etc. XP 32bit never had such a problem.
Now ive recently installed windows 7 ultimate 64bit and the same freeze happens, XP 32bit still stable no problems.
Now this is probably a hardware problem related to the extra strain 64bit OS is putting on my system but i cant pinpoint what it is, also ive run memtest86 for 2 complete passes and no errors, so my RAM isnt faulty...im all out of ideas