XP freezes overnight

[RobH]

I recently recieved a computer for repair from a friend of a friend.When I recieved it, it would lock up in a matter of minutes, I found the hs/fan on the video card was at fault, and replaced the video card, blew the computer out and sent the fella on his merry way.
He called back the next morning saying the computer ran well but frooze after being on over night.
I have checked the computer over and can find no other problems,The computer is a compaq presario with a 750 mhz duron/256 meg ram.The mobo is a VIA chipset, and originally intended for ME.
He had seen a fella before me (remember looking at this was a favor for a friend)who had loaded XP in the computer, so I really dont know how long XP has been apart of the life of this computer.
The disk he gave me to use (all authentic with COA) was an older copy (before SP-1).
I finally relinquished and reloaded windows-fresh install,(also beefed up the PC133 with an additional 256 meg ram) and ran overnight without freezing.
Last night I loaded SP-2 and behold this morning it was locked up.
I believe the problem lies with SP-2 and the age of this computer. I have nothing other than the operating system on the computer.
any ideas?
Compaq presario 5000
750 mhz duron
512 pc133 (remember I beefed it up)
20 gig Quantum fireball
VIA chipset mobo
52x cd rom
ATI 16 meg TNT video
TIA...Rob

[glc]

Disable all power management events and run diags on the ram and hard drive.

[RobH]

Ran Maxtor extended fitness test on HDD- and doc memory on the ram- both passed without a hitch.
Im still under the thought it has something to do with SP2, though I searched the knowelege base at MS without luck.The only time it ran all night without freezing (and it does take all night)was when I had done a fresh install of XP without putting SP2 on the computer...
Any other ideas???TIA

[EzyStvy]

Device Manager-> Mice - Keyboard - USB hubs -> look through all of them and disable any power management features.