Rebooting Problem with Q6600

I have a Q6600 OC'd to 3.2Ghz and DDR2 1066 Ram. I'm using the Gigabyte UD3P board as well. My power supply is 750W Corsair along with a HD 4890 GPU.

Recently, I'm having a serious problem with my computer either failing to post three times before startup and/or making it to the Windows login screen and then restarting. I have had my computer at 3.2Ghz for a while and had run tests to make sure it was stable. The memory would never work at 1066 speed so I had it clocked down to 800. Should I lower the memory down to 667 speed? I'm clueless as what to do. I lowered my clock to 3.0 on the cpu and the problem persisted.

Thanks for any help you can give.

Well, you have a gigabyte UD3 series! Go into your BIOS and save your current BIOS settings to CMOS.

Then, load the fail-safe settings.

Did you test with Prime95 and Small FFT test(this should error before a crash)? it stresses the crap out of the cpu, use blend AFTER to make sure both cpu and ram are good.

Sometimes, you need a bit more voltage to the cpu. If you have 4 stick of memory, add 0.1 volts to the recommended voltage(very few sticks do 1066 @ 1.8 volts).

EDIT, With the OC off, you can see if its a OC issue or not. Also make sure you have the latest bios

With a gigabyte board you can download the bios to a fat32 formatted flash drive and flash it from within the bios itself.

Save the bios file(if its a .zip thing, make sure its unzipped) to a flash drive (has to be in fat32)
Reboot with the drive still in the usb port.
Enter the bios with DEL then select Q-Flash from the bios screen or press END on post to enter the Q-Flash utility.
Select your bios file to flash and it should start the flash
NEVER POWER OFF DURING THE FLASH AS IT CAN KILL THE BOARD.

If your issue did not happen at the start, i would guess its not a bios thing. Still loading fail safe never hurts.