Windows 2008 keeps restarting itself

Some simple troubleshooting methods here:

1. In Safe Mode (that's a good sign that you can boot into Safe Mode, BTW), go into the MSCONFIG utility and use the process of elimination with the Services, Startup and General tabs to hopefully isolate the potential causes of the problem. That will give you a great base of operations to fan out from in the troubleshooting process.
2. Hopefully you can then boot into normal mode and uninstall the Windows updates that you previously installed. BTW, uninstalling doesn't work in safe mode since the Windows installer service doesn't start except in normal mode.
   3. Having said that, can hack Windows machines to uninstall even in safe mode using this method. Your mileage may vary.
3. You could go semi-scorched earth and repair the boot files using the installation disc: http://social.technet.microsoft.com/Forums/en/winserversetup/thread/cd3d665f-3d95-4617-946d-55d8c03448fe

If you take route number 1, let us know what you find out.

Sounds like you have a hard drive failing or some other kind of hardware. Can you swap drives and test again?