If your user profile is corrupted the last resource is to
1. Back up everything from your old profile such as My Document, Favorite and others.
2. Create an administrator account.
3. Click Start, type regedit in the Search box, and then press ENTER.
4. In Registry Editor, locate and then click the following registry subkey:
5. In the navigation pane, locate the folder that begins with S-1-5 (SID key) followed by a long number.
6. Delete all the number with .bak at the back.
7. Logon as local administrator.
8. Unjoin and rejoin the domain.
9. Logon to the domain then you will have a new profile created.
This is an extreme action, or shortcut if you like to call it, to recover the user profile. The step by step to trouble is here http://support.microsoft.com/kb/947215.