There is nothing more to add other than there must be some computer setting to which the newest version of Firefox is sensitive or conflicting with something while most other IPs in the world that are not sensitive/conflicting. I just don't have time to research this problem for hours on end considering I have three IPs that work fine, even though historically I've liked Firefox best. The version of Firefox being used did work well consistently until the new version was installed recently when it sometimes worked and now never works. I've uninstalled older and the new version and re-installed the new version usually without success.