You can use tsdiscon.exe to disconnect a terminal services session or logoff.exe to terminate the session.
tsdiscon.exe disconnects a session from a
terminal server. You must have Full
Control permission to disconnect
another user from a session.
If no session ID or session name is
specified, tsdiscon disconnects the
current session. The console session
cannot be disconnected.
Any applications that were running
when you disconnected the session are
automatically running when you
reconnect to that session with no loss
logoff.exe Logs off a user from a session and
deletes the session from the server.
You can always log off from the
session to which you are currently
logged on. You must, however, have
Full Control permission to log off
users from other sessions.
Logging off a user from a session
without warning can result in loss of
data at the user’s session. You should
send a message to the user using the
msg command to warn the user before
taking this action.
If no ID or name for the session is
specified, logoff logs off the user
from the current session. If you
specify a session name, it must be an
When you log off a user, all processes
end and the session is deleted from
You cannot log off a user from the
Details are here http://technet.microsoft.com/en-us/library/cc776289(WS.10).aspx