Logon screen

I have a computer that is part of a network that I am working on. The problem is that when it is started up it won’t go to the Network logon screen. Instead it boots right into Windows (like an UNnetworked computer might). You can, however, log off and the logon screen does come back up. Of course that makes sense, but the other doesn’t. This PC is configured just like the rest and I’ve done everything I can think of. Any suggestions?