Click Start
Click Run
Type Regedit
Open the following folder:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\SpecialAccounts\UserLis t
Right click in the open space to the left
choose New
Click DWORD Value
Type the missing user ( Administrator, etc. )
Enter
Right Click on the user
Change the Value data to 1.
Close the registry
Open the Control Panel and notice that your missing user has returned!!!