windows 2000

My wife's old computer was used for work and had a network co. name and network policy screen that you have to ok to continue to log in. Once you get past this screen you get a log on to windows screen with user name and password. User name is still the same but I don't know what I did in trying to remove this start up in the configuring of this page. How can I get back into windows and how do you remove this type of log on from windows 2000 professional