|If the problem survived a factory restore than the problem is hardware related. Run Memtest86 from bootable CD to see if your problem is your memory, run all tests. If there are any errors or it freezes then rerun with one stick of memory at a time to confirm memory problem and which is bad. Dual channel memory is best replaced as pairs though.|
If you get a complete test without any errors then run the hard drive utility from your hard drive mfg's website (open and read brand or use seagate's seatools which are reported to be universal) from bootable CD to test your hard drive.
You have to be a little bit crazy to keep you from going insane.