I saved my passwords on paper and do not believe I have mislabeled them or forgotten them. But every time I go to install plugins for video or check for software update it asks for a password and wont authenticate using my password. Ive tried the reboot shift select. Then ls /home (user) then passwd (user) to reset from the menu that loads prompt screen. It goes as far as entering my second new password and then rejecting the action.
Ive tried everything else I know (which I admit is little) short of a fresh install. Which Im afraid I'll need help with as well

Help Help Help! I hate windows and want to never go back