I recently restarted my computer after an update prompted me to. Since then I cannot log in. It makes the drum sound, but kicks me back to the login screen. I can't even login as guest, it does the same thing. I can't Ctrl-Alt-F1 either, due to some dual monitor bug, it either says kvm disabled, with no command prompt or there is a blue line at the top of the screen, or the monitor goes to sleep. I did manage to log into recovery, get a root shell prompt and tried fixing packages, deleting /cache, .Xauthority and .ICEAuthority. I've found several posts with similar issues but no resolutions that work for me.