Comment 2 for bug 994778

Is it possible your system has booted into a read-only file-system mode? (I've already reported that bug, and Mozilla won't respond either, presumably since it can't write any session or cache files )
Is it consistent upon multiple reboots? (mine is only intermittent, usually it boots ok)
Are you able to open a terminal window via ctrl-alt-T? In a terminal, do you get error msgs about locked files or other access problems? (For example, running 'sudo apt-get update?
What do you get with
Have you run 'sudo apt-get install -f" ? (fix packages)
What file permissions on your home dir do see when you run 'ls -l /home' ?