Forgot password and changing it

I recently installed SAV 8 for Mac on my computer and got an alert that I have a Trojan quarantined.  In order to clean the threat, I need to authenticate by putting in my password, which I promptly forgot or that I never got to this step in the installation process.  When I clicked on the question mark key, it gives me instructions for changing the passowrd but it does not allow me to do this.  What am I doing wrong?  I do not see a dialog box telling me to put in my Apple ID and then reset the password.  Can you please help so I can clean up the threat?

 Thanks.