On Windows 7 the computer freezes for about 5 minutes once it gets to "Shutting down...". I can't remember when it started happening. I just lived with it for a while.

The first thing I tried was a full scan using Microsoft Security Essentials. This did not solve the problem.

I then went into msconfig and turned off everything I could get away with in the startup and services tabs. This did not solve the problem.

I then uninstalled every program on this computer save the most basic programs. This did not solve the problem (did not uninstall drivers or catalyst).

I then went through and turned off every single service and did a reboot. This did not solve the problem.

I then booted into safe mode and just tried shutting it down. The problem even happens in safe mode.

I have tried examining the event logs but with no success. They just say things like "blah blah has entered the stopped state" with no real clues about what program is causing me all this grief.

*it may be worth noting that Ubuntu is installed on the same computer and the ubuntu boot loader is the one being used.