A: On a non-Remote Desktop Session Host, you can have two concurrent administrator logons per server. Additional administrators who try to connect will see a list of the two existing sessions and will have the option to disconnect one of the existing sessions, including the console session.
Microsoft has released a hotfix for this problem. Once it's installed, you can create a registry value to be created, HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Terminal Server\Winstations\DenyConsoleDisconnect. When you set that to 1, the admin who's trying to make a third logon session won't see the console session will not be listed as a disconnect target.