Recently I installed Ubuntu 12.04 (first time on Ubuntu).
I have my normal "administrator", and another Guest account.
I was experimenting today with the user accounts, and set my "administrator" account to "standard" in user account settings.
Now whenever something asks me for authentication, it gives me failed message.
I am using the same old password, didn't create new accounts, just changed privileges. I'm sure that the password is correct, because I can still log in.
I tried logging in to root from Terminal, but it gave me that I'm not one of the