i have just upgraded to ubuntu 11.10 i had to go into settings i dont know what i have done but now i can only log in as a guest when i boot up i get the message "can't update ICE authority file. /HOME/PAUL/ICEauthority" Also when i try to get into the home folder i get "you dont have the authority to access this folder." what do i do to get into the home folder, i have the passsword but it wont give me permission as a guest but i cant log in as anyone else not even my own name
Since you mention that no user accounts work, you will need to reset the administrator password from recovery mode. There is already an excellent Q&A describing this so I won't reiterate that here (see below).
When you have logged into the administrator account, you can reset the user ICE-Authority file as follows:
Open a terminal
logout and then login to the