I recently upgraded from Ubuntu 11.10 to 12.04. If it makes any difference, my system is a Dell Inspiron 1520.
I encounter a problem whenever I shutdown or restart; it kills all running processes (as far as I can tell), but once I get past the shutdown text screen and the screen goes black, my computer doesn't power off. The fans still run and the screen is still on, etc. I have to hold down the power button in order to complety shut down.
Does anyone know how to resolve this problem?