So today I woke up and couldn't log in into my user (the screen flashed and went back to the login screen), following advise elsewhere I deleted .Xauthority. Now I just get a black screen, I can only use tty's. I reinstalling unity but it also didnt work.
Edit: I installed gdm and it also doest load. It just shows the ubuntu loading screen forever.
grep "] (EE)" /var/log/Xorg.0.log
shows you the errors of the X server.tail /var/log/syslog
displays general problems. Add some logfile output to your question, please. – mniess May 11 '14 at 19:40