Random lockups

The reason I haven't posted recently is that I moved house at the end of January and have had lots of stuff to sort out before getting back to the PC problem.

There's never anything in the event log to suggest a cause for the lockups, unfortunately & my 'brainwaves' have all led me up the garden path...

I was convinced it was software related since the problem never manifests itself in one Vista install but does in the other (same install source) and the XP install. I ruled that one out after an attempt to clean-install Vista again on the new SATA drive and it froze before it had even reached the desktop for the first time.
That made me think of the config and particularly that the problems happen on OSes installed on SATA drives while the stable Vista is on an IDE drive.
I thought I might be getting somewhere but Googling only threw up people with short lock-up problems so that petered out leading me to think I needed a new mobo. :s

Yesterday morning, however, I found the machine switched off after I'd left it booting into the stable Vista the night before. Subsequent power-ups allowed me use for at most an hour but more often it didn't get to the desktop before -plink- it powered off without warning.
This afternoon I swapped out the 650w modular EZCool PSU for a noisy generic 500w from babyputer upstairs and it's been fine since then.

Who knows, maybe it's that PSU after all, in which case it's the third EZCool PSU that I've had go tits-up under warranty - I paid the extra for an upgrade each time.

Bloody thing locked up about 5 minutes after that last post. :(

It's not instantly powering off now though so I gotta add a PSU to whatever I need to fix this thing.

Went to the local Computer Fair and got myself a KingWin 600w modular PSU this afternoon. Slightly cheaper (though more than I'd prefer to pay) than the Hiper model that was the only other option apart from a few hundred EZCool units that I steered well clear of.

As far as the lock-ups are concerned, I think I may have stumbled upon a possible solution.
Browsing possible motherboards for an upcoming job, I came across a customer review of another NF590 board where the guy said he had lockup problems until disabling the 'Cool n Quiet' feature so the last time my machine locked up I disabled it and it's been running for two days without freezing.
I'll be running another clean Vista install on the new SATA drive later to check further as that has been the most troublesome.

well it's been nearly a week of constant use in XP and another fresh Vista64 install without a single lock up so I'll consider it the final solution... enabling AMD's Cool N Quiet BIOS feature causes freezing on some systems.
Thanks for listening.
Someone can close this thread now.

Congrats.