Hard to believe, but it's true !
I've had a nice machine that came with windows vista, 64 bit; but it locked up constantly. Over the months i've tried many things, even went with installing windows xp 32 bit, same behavior. Finally I had concluded it must be a bad peice of hardware causing this mystery lock-ups...and let the thing become a paper weight.
Finally decided to try windows 7 last week, popped the dvd in, formatted the hard drive (no sense upgrading a non-working os) and installed windows 7.
Wow, windows 7, right out of the box, my machine finally works.
It's been on for a week without a single "lock-up", amazing ! Micro$oft may have gotten one right.