Windows 7 holds a list of all the user accounts on the PC. You might not want to explore some of the accounts you created as admin (for example: service account) hide user logon screen is a registry tweak that may help on this scenario.
1. click ‘start’ button < type ‘regedit’ < press ‘enter’
2. Browse your registry to HKEY_LOCAL_MACHINE\SOFTWARE\ Microsoft\ Windows NT\ CurrentVersion\ Winlogon.
3. Right click Winlogon folder<select ‘New’<select ‘Key’.
4. Name the new key SpecialAccounts.
4. Right-click the SpecialAccounts key, select ‘New’< select ‘Key’<type ‘userlist’.
5. right-click and select a new ‘DWORD value’.
6. Enter the name of the user account that you wish to hide as the name of the DWORD.
7. Close registry editor.