Are you attaching via terminal services, if so go start/All programs/administrative tools/terminal services manager, on the users tab it will show all sessions. Just right click on the desired session and either connect or logoff.
You will probably need admin rights to do this, if not, ask the sys admin to clear the sessions, preferrably logon and log the session off as this will close all files.

>>do thison the server:- Start/All programs/administrative tools/computer management.
>>Then under system tools/shared folders/sessions right click on the desired session and select "close session"
>>
>
>I see nothing there, I don't see other people sessions. I guess I don't have Admin rights on this server.