[Start] [Run] [Regedit]
Go to: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsNT\CurrentVersion\Winlogon\SpecialAccounts\UserList
Setting for Value Data: [0 = Account is Hidden / 1 = Enabled]
Exit Registry / Reboot
While the account is hidden on the Welcome screen, note that the account profile will be visible in C:\Documents and Settings or wherever user profiles are stored as well as in Local Users and Groups.