right click and run as admin, also confirm that you have net framework 3.5 (I think it's SP1 that you require). Just having 4 installed does not mean you have 3.5 - they are not backwardly compatible
Having 3.5 sp1 didnt solve it for me. Still only missing the login screen.
And running as admin didnt make any difference
I use Windows 7 Ultimate 64bit