Xp welcom screen missing- blank screen appears

i have manually tried to install a new login screen to no success, but in the process i have lost the welcome screen.
now when i log off a black log on screen appears i want to restor the welcome screen what can i do? i have tried manually restoring the welcome screen this way
= start/Run/regedit/hkey_local_machine/software/Microsoft/windows nt/current version/winlog
i then modifed the ui host to (C:\WINDOWS\system32\userinit.exe,)

what can i do now?

Try going into User Accounts in the control Panel. and resetting the way in which users log on to include the welcome screen. That should do it.