[Shiromagius]

If you have Norton Ghost, that would be a good way to "clone" your hard drive. Have you unchecked the "Automatic Restart" box in System Props -> Advanced -> Startup and Recovery settings? Maybe instead of your computer restarting, it will give you one of its lovely blue screen of deaths and you can find out exactly what is causing it to restart. Another option is to check your event viewer to try and look for what causes these random restarts. Could be video drivers, who knows.