Aero Has Stopped Working (Administrator Account)

Aero was working (via RDP), but has stopped.

The personalization screen says: 'One or more of the themes has been disabled by Remote Desktop connection settings'.

I have performed the steps mentioned http://blogs.msdn.com/b/rds/archive/2009/06/23/aero-glass-remoting-in-windows-server-2008-r2.aspx (Manual steps to enable Aero Glass remoting on Windows Server 2008 R2), but that didn't work.

Any ideas?

Thanks.