This is a hail Mary. Microsoft changed the behavior of Windows, supposedly for security, so that clicking the Firefox button to make it the default web browser is no longer allowed. Instead, I get taken to the default apps section of Settings, where the only choices are Edge and Internet Explorer. No Firefox. Same with images and with video. Microsoft is not helping with this and I'm damned if I'm wading through probably a hundred or so file extensions changing each one individually. Somebody else must have run across this problem and maybe solved it?