There is one backdoor which can be used. Since Windows 2003 there is a little known feature which helps in a “too many connections” situation. The Remote Desktop client offers an option which allows you to connect to the console. This gives you a 3rd connection. If someone is logged into the console you have to have the sufficient permissions then the session will be logged out and you can log in. If nobody is logged into the console it will let you log in.
Start -> Run -> CMD
cd Program FilesTerminal Services Client
mstsc -v:x.x.x.x /console