My new ASUS P5W DH DELUXE reboots any time

My new ASUS P5W DH DELUXE reboots any time it feels like it.
I wonder whats up with it.
No overclock, bios set to defaults.

ASUS P5W DH DELUXE BIOS 0701
Intel Pentium D 930 Presler 800MHz FSB 2 x 2MB L2 Cache LGA 775 Dual Core Processor
OCZ Platinum 2GB (2 x 1GB) 240-Pin DDR2 SDRAM Unbuffered DDR2 800 (PC2 6400) Dual Channel Kit System Memory
ATI RADION X1800XT
PC Power & Cooling SILENCER 610 EPS12V
Thermaltake Big Typhoon CL-P0114 120mm Cooling Fan with Heatsink with Artic Siver 5 Thermal Paste
Thermaltake Tsunami VA Black Aluminum ATX Mid Tower Computer Case
Windows XP HOME

Ran Memtest for two hours, passed.

Did you check temperatures in the bios?

Is all hardware properly seated in slots?

Go to jumperfree config and set to 'manual'. Then ensure fSB is at 200mhz, and EVERYthing else to Auto. In windows run dual instances of Prim95 small FFTs(torture test). If you have any questions post them.

Thanks,
I'll do that,
Also did a windows repair. That went well, but didn't help.
Dan

Manually increase the ram voltage to 1.95v. I have heard AUTO is around 1.8v and that could cause issues. Otherwise, I have read about compatibility issues with Asus board and OCZ DDR2. That's why I spent a little more money and bought Corsair DDR2 this time.

Check all of the power connectors, check if memory is set right. Check processor temperatures, just in case heatsink doesn't make proper contact.

Find out what memory voltage should it run and timings.