Lost Settings Password

I want to adjust some settings in Avast Free, but have forgotten my password so I am blocked out.
How can I discover my password, or delete it so I can make the adjustments wanted?
If that is not possible, how can I uninstall Avast and then install a new clean version please? (The uninstall asks for the forgotten password!)

only solution… reinstall :-\

Uninstall Utility http://www.avast.com/en-no/uninstall-utility

Installation files http://www.avast.com/en-no/download-software