Admin log-on gets in the way!

In a multi-user scenario where there are many users logging onto a Netware client machine with Windows 2000 Pro, the machine continuously wants to log on with Administator name and password. It then asks to change the Microsoft password to the client password. This then becomes the admin. password. When another logs onto the network with this machine, you need to know the previous users admin password to get on. this cycles around repeatedly. I am in an education environment and this is our first encounter with Windows 2000 on our network. Can anyone walk me through the procedure to disable the admin. (Microsoft)log-on. Help!