Windows 2000 Server Lockout

We had an interesting issue this morning. No one could log on to the network including the Administrator. When you tried it said it was locked and could only be opened by the Administrator. I’m an administrator so I even tried using my logon (didn’twork). What was even stranger is since I locked my machine last night instead of logging off, I had access but could not terminal service into the server. It eventually let us in but I don’t know how. Anyone have any suggestions.