Well, I don't know what else to suggest.
Did you use system restore, or "last known good" at any stage?
There is no way a password is created on the genuine Avast without user input.
I use Revo also. And I've read pretty good things about Regseeker. But why not put the uninstall utility, designed for one purpose, to the test?
And was there anything in the quarantine when you uninstalled it? And (if so) were you prompted to save those quarantined files?