hello cowboybob, other affected uses with similar symptoms have reported that this may be caused by adware/malware.

please go to the firefox menu ≡ > addons > extensions & remove any suspicious entries (toolbars, things that you have not installed intentionally, don't know what purpose they serve, etc).
also go to the windows control panel / programs and remove all toolbars or potentially unwanted software from there.
finally, run a full scan of your system with different security tools like the free version of malwarebytes & adwcleaner.

Troubleshoot Firefox issues caused by malware

Thanks, philipp.

I did as you suggested, in the order as suggested.

What finally worked was the total drive scan (using AVG Security 2014), which found all kinds of stuff that it eliminated.

I very much appreciate your responding as quickly as you did. All things considered (used to work for Apple back in the '80s) I should have thought of that myself. You know how it is ...

cowboybob (Paul)