Hi all I have a nagging problem I built a PC, specs:
Asus p5n-d
Intel Core 2 Quad Q9400 2.66 GHz
Geforce 8400(reading 7300?)
OCZ ddr2 800 pc6400 4gb
2.5 Tb Hdd
Antec 650 pws
I'm running win xp pro 32 bit I know I should be running 64 bit but that is all I have right now.

Problem is after a couple of minutes running it locks up and some times just reboots?I tried all, cleaned scanned for virus, swapped ram sticks,checked and recheck bios settings,not running raid by the way. Tried 3DBenchmark ran first test locked up during second ran again both test no prob? Ran again locked up?no wares on PC no virus? Any help would be great.

What are you doing when this lock up occurs ?

I assume you are running all of the latest drivers, including chipset BIOS and GPU.

Yes I am on both

Have you run a chkdsk on your HD. Sometimes a few bad sectors in the right places will make a computer do things you never thought possible, plus high density HD's are prone to error.