Initially chaek the connections (Active / Non active) on the server from comamnd prompt of another Windows server in the same network.
Open command prompt and fire Command — query session /server:win7
where win7 is server name.
Now Kill the connections which are not active.
Command — reset session 1 /server:win7
where 1 = Session id.
PS – This procedure needs to be carried out on another Windows server in the same network.