I have a Dell Dimension 2400 with Windows XP I am helping a friend with. I wanted to get rid of the log on screen on start up. I used "run" command "control userpasswords2" and unchecked the "user must enter a username and password" box. When I restarted the computer, the log on box appeared with an unknown name in the user box. I tried clicking ok and received the message "System could not log you in. Make sure username and domain are correct, then type your password again." I tried typing in "admin" and got the same message. There is no password or user names set up on this machine. I have tried safe mode and get the same screen. How do I get past this? Or, how to reload windows xp without signing in. Thank you for your help.