I'm new to Ubuntu and I've been using it for about 2 weeks now and I have the following problem: I installed the NVidia driver version 331.38. Then I restarted the computer and after I logged-in a dialog popped up with the following error message: Could not apply the stored configuration for monitors - Error on line 1 char 1 : Document must begin will an element (e.g <book>) Any suggestions on how to proceed?