Computer freezing

[Exterous]

Here is the background story:
-Old video card (ATI HD2900XT) died. While it was in RMA I:
-Borrowed an ATI 4670
-At some point my computer shut down and booted straight to the 2nd HDD (bypassing the defualt boot drive)
- I restarted and it booted correctly BUT (through various methods)
- I found thousands of orphaned/corrupt files on it - preventing many important Dlls to run
- Reinstalled OS
- Now it will sometimes freeze even when doing simple things like scrolling down a web page.
- I have run chkdsk again, the WD diag tool and our Companies diag tool on the HDD and it passed all of them with no errors

I am thinking I might have to replace my motherboard.
Any other thoughts? Agree/disagree?

Thanks guys!

System specs:
E6400 CPU
GIGABYTE GA-965P-DS3 LGA 775 Intel P965
Antec Neo Power 500 500W ATX12V
3x2GB Corsair RAM

 

[mpilchfamily]

Try running Memtest. There is a chance that the RAm is going bad. With bad RAM the data sitting in the RAM may be getting currupted causing the problems. WHen the system goes to write that bad data back to the HDD the drive becomes currupted.