I found this in a few different places around the 'net - hopefully it's helpful:
Change the Logon Window and the Shutdown Preferences in Windows XP
Setup configures Windows XP to use the friendly Welcome logon screen and the shutdown buttons, if your computer is installed as a home computer (a computer where a network domain has not been specified).
This article describes how you can enable the classic logon screen used by Windows XP Server that resembles the following example:
Log On to Windows
User name: _____________
To temporarily use the classic logon screen, press Ctrl+Alt+Del twice on the Welcome logon screen.
To configure Windows XP to use the classic logon and shutdown screens for every logon session, do the following:
- Click Start, and then click Control Panel.
- Double-click User Accounts.
- Click Change the way users log on or off.
- Click to clear the Use the Welcome screen check box.
Note: If you disable the Welcome logon screen, you also disable the Fast User Switching option.