Again there really is very little information to work with here.
Save the password where ?
I honestly don't know how you are changing your password ?
Ordinarily I would expect to do this you would have to either enter the old one of somehow have it send you an email.
Seems you bump into more problems and immediately threaten to uninstall Avast.
Surely you would/could have saved your forum logon details in 'your browser' (which is) ?