There are several HowTo's on this. You don't have to delete all accounta, re-install Windows, etc...
This won't work if you are on a Domain.
This works if you have a bad profile record in your list of accounts. In my case, adding/deleting an account caused one of these.
Regedit
Find:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList
Delete any in the list that do not have a ProfilesImagePath record.
If that is not the case, refer to the HowTo for a few more examples.
