I have used Mythbuntu for at least 5 years now with very few problems. I am running 12.04 and everything was running very slow so I rebooted the computer (runs both front and back end). I came to the general login screen and entered my password and after a few seconds the screen turned blank, then a few seconds of that, then back to the login screen. I can login as guest, but I have no permissions to do anything (like start the front end). I don't know all that much about ubuntu, so please reply as though I know very little. Thank you in advance for your help!