This is only a guess, but when the Hard drive was moved to another computer, Was Windows Re-installed or was the original configuration on the Failing PC used? That could be a pointer.
Further more, Can you confirm that the Ram combinations that you've used are supported by your motherboard? IE DDR 2, DDR 3 and
what speeds are they? Also, What Cas Latencies do they have?
Some Motherboards don't like Ram with certain Cas Latenies or overclocking.
I suspect if the Video card was damaged, that display issues would be happening and there might be noticeable Burning on the Video Card.
I would do as the other one says, and run the Hard Drive test, but I might also Try to boot from a Live CD.http://en.wikipedia.org/wiki/LiveCD
This could eliminate the Hard drive as a problem or help you be more detailed in finding a resolution.
Edited by RandomUser, 25 November 2008 - 07:01 PM.