credit to tweakxp
1. Make a backup copy of C:\windows\system32\logonui.exe
2. Overwrite the file with your new login screen. (be sure to use the same file name as the old logonui.exe)
3. If you ever want to revert back to the old login screen, just overwrite C:\windows\system32\logonui.exe with your backup.
make sure xp protection is off
good luck