First, I should say that I am a total beginner. When answering, please do not take for granted that I understand even the most basic step. Now for my question: Yesterday, I was given the option to update to ubuntu 14.04. I clicked yes, and the system took about 2.5 hours to accomplish this task.

Now, whenever I log into my user account, I get an error message and then I am asked to authenticate my user account. When I try to enter the password, my computer freezes.

Please help, what can I do to fix this?