Process just hangs

A computer that I maintain at work has all of a sudden developed a lockup of some sort. So far I have encountered the following symptoms.
1) There are no error messages in the logs.
2) When trying to restore default settings in Internet Explorer 6 the process hangs.
3) When trying to change the start buttons behavior to Traditional start menu, the process hangs.
4) Neither of the processes in 2) or 3) creates any error messages. They just hang the process.
If anybody have any idea about what to look for I would appreciate it.