please help! really annoying win7 freezes!

hey guys,

i have just recently done a complete format of winxp 32bit and installed win7 64 bit instead.
i am having a really annoying problem.

randomly after booting up the pc will freeze. no warning, no apparent trigger and no pattern.
the only way to get it working again is off and on. its very odd, because there is nothing, it just stops.
it has happened on the loading screen to windows even, or like this time, it works for hours before crashing.
it has happened in all situations, games, videos and dvds, internet browsing. it happens every time i boot without fail. it happens tens of times a day, depending on how long the pc will be on before it stops
i have tried all the solutions i could find on this problem to no avail.

the first thing i did after installing win7 was make sure that all my drivers were up to date, well as many as i could think of, and windows isn't showing any problems in device manager.
i have had only one bsod and dont know if it is related, but it referred to "page dump in non page area" it was hard to see as it was there quick and hasnt happened again.
i have done windows memory test no problems, and run check disk with repair, still with nothing wrong.
i have done a clean boot and gone through the services to find one that may be faulty, but had no real luck there.
i found something referring to win7 conflicting with certain antivirus' so i uninstalled my avast and insalled MSE then i found somehing claiming it could be MSE that causes the problems.
im starting to think this is more common than i thought and that noone really knows, the threads based on it go right back to the beta stage.

the only thing i am left with is that it is a hardware issue, am i right to assume this? the lack of bsods makes me think windows isn't having time to shut down and the hardware is just freezing the pc.

ANY help will be greatly appreciated, i am at my wits end

thanks in advance
Goblin

Thanks for the replies!
As soon as im home from work ill do what your suggesting, do you know a good place to find older display drivers?
Im sure overheating isnt a problem im v rarely over 50o even under load but saying that im waiting for a new much cooler case anyway.

really thought i was getting somewhere, each driver i tried stalled the freeze for about 2 hours after installed, i tried three whql signed drivers, and one beta, because it was newer. however nothing made an impact, after the initial freeze-free period it was back to happening pretty soon after the restart. it doesn't happen in safe mode at all though. should i keep trying older drivers?
i found nothing i understood in event viewer however in the "view reliability history" part of the action centre i did see a few video hardware errors. they don't happen as often as the freezes but seems to be a problem.

ok its booted into clean boot, i only have like 4 services that aren't microsoft!

i have tried this before but to determine which service could be faulty not to test drivers. and i didn't check the hide microsoft services button last time either :S is that really bad?