1) Open up RegEdit
2) Navigate to [ HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionWinlogonSpecialAccountsUserList ]
3) Look for Administrator on the right side, if not there create a new one by right-clicking and select new dword
4) Select Administrator in the right panel and set the value to 1
5) Reboot machine



TIP: REPLACE [] WITH STANDARD HYPERTEXT PROTOCOL.
TIP: REPLACE WHATEVER IS BETWEEN THE [] WITH YOUR INFORMATION.



Hope that helps!