Downloaded and installed about 20 updates today. After installing, it said that a restart was needed to finish. I clicked to restart and everything was fine: shut-down and restarted. However, since then, when I try to shut i down, I get the text on the screen that says something to the effect that it is waiting for remaining processes to stop (like it has always said), and then the Xubuntu screen comes back up (like always), but that where it stays: it never shuts down: I have to hit the power button to shut it off.
I am running Xubuntu 12.04 on a desktop, 3 gig RAM, 2.8 dual core.