I am running 12.04 LTS on a VM. I encountered a problem with the screen being black and the familiar orange background showing for a fraction of a second when clicking or resizing the screen. I had to shutdown the machine and now I have no GUI. I only get a black command-line interface.

As some other posts suggest, I attempted:

sudo service lightdm restart

This doesn't work for me because it gets stuck at this point:

Skipping profile in /etc/apparmor.d/disable: user.bin.firefox
Skipping profile in /etc/apparmor.d/disable: user.sbin.rsyslogd
* Starting AppArmor profiles                                        [ OK ]

Any ideas?