Over RDP Ctrl+Alt+Home - Start menu

>I've been having trouble with my office machine and while accessing it remotely from home I eventually ended up with a *totally* blank screen! So how can you remotely reboot machine from that state?
>
>Ctrl-Alt-End brings up the windows security dialog!
>
>See http://blogs.msdn.com/oldnewthing/archive/2006/10/20/849575.aspx