I updated from Ubuntu 11.10, I had installed also XFCE on that version but mainly used Unity, after I upgraded to 12.04 when I shutdown it doesn't shutdown it remains in a XUbuntu splash screeen. I mention that I did't installed, XUbuntu but probably installing XFCE installed also that splash screen.
How can I fix that and make the system shutdown without using hard shutdown?
Run
sudo shutdown -h now
in the terminal window.