1. Open Start menu then click on RUN.
2. Type in the Run Window Regedit
3. Windows Registry editor will open then navigate from the left panel :
HKLM\Software\Microsoft\WindowsNT\CurrentVersion\Winlogon\SpecialAccounts\UserList
4. Create a new DWORD, setting its name to the name of the account you wish to hide.
5. Then set its value to 0 to hide it.
NOTE : This account isn't completely hidden because it is visible to administrators in Local User and Groups and also the profile is visible in the Documents and Settings.
Now How To Login In it after you have hidden the account :
1. At Welcome screen, and you want to login to this account.
2. Press Ctrl+Alt+Delete twice and it will display the log-on promt.