My PC keeps freezing, after its been formatted

Hey there
im having problems with my pc, i have two of the exact same pc's motherboards are the same, CPU's are the same only diff is GPU's, Cooling, Ram, and the one im having probs with i upgraded and was running Windows 7 like a champ but a few off my production programs would not run so i formatted it And Ran XP immediately after reformatting it froze so i ignored it And Just restarted then it did it later again and it was doing it during important work which i kept loosing, it then stop and now its doing it again but worse, really frustrating, whats confusing me is there were no probs wen running Windows 7 now all of a sudden this and the other pc has mo probs whats so ever.

Not too certain on wat specs u need, Not certain on make of the mother board

1 gig ram
2.4ghz processor
80 gig hard drive
Aopen Dvd-rw drive
256mb Nvidia Gpu

Any help will be appreciated

I am assuming that you are not getting any BSODs, so perhaps a good idea will be to take a look at windows logs. You can find these in Control Panel > Admin Tools > Event Viewer.

Please take a close look at Red/Yellow tagged events in System and Application logs and see whether something useful is being recorded.