Hi Tom,
Depending on version (but then maybe not), it disables the Welcome Screen
and gives a msgina.dll error message.
The msgina.dll (Graphical Identification and Authentication dynamic-link
library) should be listed in C:\Windows\System32 - Application extention.
This can happen if you installed PCA, VPN Cisco Client, etc. Normally
removing any of the above, the msgina.dll is replaced.
Check here for gina.dll, ginamsi.dll, or CSwgina.dll if either is listed,
remove it, reboot.
Start/Run/Regedit
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\Current Version\WinLogon.
In the right pane, remove the entry for (XX)Gina.DLL.
Restore the Windows XP Welcome Screen (Gina.dll) Line 45 - Right hand side
http://www.kellys-korner-xp.com/xp_tweaks.htm