If you have problems with Windows XP logging off — that is, the system inexplicably decides to wait for about a minute before it proceeds with log off or shutdown — you may want to give Microsoft’s UPHclean – User Profile Hive Cleanup Service a spin. It just helped me with this problem that was harassing me for the past full calendar year.
It installs as a service so it’ll keep working.
Now, I wonder why this service is not included in Windows themselves, or at least in a service pack – why ship a broken OS?