Windows 7: Fresh install of Windows and it keeps recovering from an unexpected cr

My fathers computer keeps crashing and restarting even after a fresh install of windows.
Specs:
Gigabyte 890GPA-UD3H Motherboard
AMD Phenom X6 1055T (only running 4 cores at the moment)
4x 2GB OCZ DDR3 PC8500
Linksys WMP54G wireless adapter

Several memory tests have come back fine and I ran PassMark BurnIn test and it crashed half way through but the only errors if found were with one of the DVD drives. After Re-installing Windows the only things I've installed was Chrome, Microsoft Security Essentials, the drivers for the WMP54G and the BurnIn test. I also updated all the drivers listed in Windows update but have been holding off on all of the updates them self until the computer is stable. Also I haven't installed the drivers that came with the Motherboard but the only one it needs is the USB 3 and since it was having the same problems with them installed I've been holding off on those also.

Any help on what might be the cause would be greatly appreciated.

So I was just reading that the Memory tester in windows sucks so I started a test with Memtest86 and so far there are like 40,000 errors and not a single pass. That just doesn't seem right. Any input?