When a profile is not deleted correctly from a computer, the user(s) may have difficulties logging in correctly. Most of the time, user(s) are logged in with temporary profiles. Here is a way to fix this via registry.
Open the registry by launching regedit.exe from ‘run’.
WARNING!!! Improper use of the registry may cause damage to your windows.
1. Expand HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList
2. Click on each of the profiles starting with S-1-5-21 and delete all that are affected (hint: Look at the ProfileImagePath, if it says the user)