Computer randomly freezing. I am out of ideas

[Scottifer]

Hello,

One of my computer builds keeps freezing, I've built up about 5 of them this one was I think third in the build order. Here are the hardware specs
CASE LIANLI|BLACK PC-K62 RT
Hard disk 640G|WesternDigital WD6401AALS % - OEM
DVD BURNER HP | 1270I LS SATA R
Motherboard ASUS P5Q PRO TURBO 775 RT
VGA nVidia GeForce 01G-P3-N945-LR 9400GT 1G R
Power Supply ThermalTake|W0318RU 600W RT
CPU INTEL|Core 2 Quad Q8400 2.66G 1333 R
Memory 2G Kingston KVR800D2/2GR R
Running Windows 7 x64

In trying to fix the issue I've completely wiped the hard disk and reinstalled
replaced the hard disk
replaced the memory
took apart and slowly carefully put back together
still has the same issues of freezing, there is absolutely NO pattern in the freezes either, it just happens randomly throughout the day.

I really need some direction, does anyone have ideas of what else I could try?

 

[Hard Line]

have you tried a dif PSU?

 

[geofelt]

Download and run memtest86+ for several full passes. You should get NO errors.

If you are overclocking anything, back it off.

Stress test the cpu by running prime95. Set the option for rounding checking. Let it run long enough to stabilize at maximum temperature.

Check the motherboard web site, looking for any bios updates that might address your symtoms.

Verify that all your drivers are current. graphics and chipset particularly.

Are all the fans verified to be working? Particularly the cpu and graphics card fans.

Is case cooling possibly an issue? Run with the side panel off, and direct a house fan at the innards.

Is your wall outlet properly grounded? Are there variations in wall voltage? Perhaps a small UPS might be in order. It is a good idea anyway. APC makes good ones.

It is possibly a PSU problem, XFX and Corsair would be on my short list for a replacement.