The two things I would try are sfc /scannow with your home OEM in D: drive,then chkdsk /r for C: drive. Failing this it could be a power, heat or RAM memory problem. Sorry I can't help more without further information.
When my brother opens up any random program on his PC running XP home, in about 15-20 minutes, it restarts automatically, has sent it to place where he bought it, they checked it out (for a fee) and they found nothing wrong hardware-wise, data trasfer over a gig causes it too, and its off and on, tried virus scans and came up with nothing, spyware scans came up with nothing either. Anyone know what's wrong?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic