By default, Windows XP does not show the Administrator account as an option to the log-on screen. The Administrator account is only shown when you boot up on Safe Mode. If you want the Administrator account to show up on your log-on screen follow the directions below:
Step1: Backup the Registry
Be very careful when changing Registry Entries. Back up your registry first as following: Start>Run>regedit then go to File>Export and select Export Range All.
Step2: Enable the Administrator account to show up on log-on screen
Go to the following registry entry:
HKEY_LOCAL_MACHINE > SOFTWARE > Microsoft > Windows NT > CurrentVersion > Winlogon > SpecialAccounts > UserList
Now, go to the right side pane and right click with the mouse selecting New, DWORD Value. Give the name “Administrator” to this DWORD value. Double click on the DWORD value and make it numerical “1”.
Reboot and you should see the Administrator account shown up on the log-on screen.