To check the sessions on a Windows Server 2008 Terminal Server do this:

• Start Server Manager (either right click Computer and select Manage, or start Server Manager from Start → All Programs → Administrative Tools → Server Manager)
• Expand the Roles, and go to the Terminal Services role.
• Select the Terminal Services Manager

There are three tabs: users, sessions and processes:

You can enable / disable logons on terminal servers like this:

change logon /enable
change logon /disable

Query the current setting:

change logon /query

If you have sysinternals installed you can do it from remote as well:

C:\Documents and Settings\sjoerd>psexec \\<servername> change logon disable
PsExec v1.55 - Execute processes remotely
Copyright (C) 2001-2004 Mark Russinovich
Sysinternals - www.sysinternals.com


Session logins are currently DISABLED
change exited on <servername> with error code 1.