The motherboard, CPU and heatsink

I think your hard drive may be getting bad sectors on them if its hanging on you frequently.

Save the important data that you need and then wipe out your drive and restore it back to factory defaults.

If its still hanging on you frequently, then at that point replace the hard drive and restore it back to factory defaults.

It will be a good idea to backup all your data and have your hard drive formatted and your OS re installed, this pretty much will fix that issue.

Have a look at this post and see if it applies at all. http://www.fixya.com/support/t1541373-gateway_gt4022_motherboard_failure Your problem sounds like one of the possible failure modes of bad capacitors. I had a ASRock mobo that worked great right after cap replacement. I gave up and got something else after the caps failed for the third time.