Press Ctrl-Alt-Del at the login screen. I forget if it's once or twice, but it should bring up an alternate login screen where you type in the username you want.
I am using WinXP, SP3, and have three persons using the same computer. The configuration now shows all three users on the blue Welcome screen. How can I select Administrator account under these parameters? The three users are configured by name and have the following priviliges. Administrator/User and two limited users.
I realize I have the ability to make system wide changes, but I would like to do so under the straight administrator account.