Thanks for your help, JustinC. Unfortunately, my friend I have tried your suggestions amongst many others for getting on for 2 years approx, now. To no avail, i have to say. Firefox never gets back to me.
Please let me clarify exactly what the problem is.
If I go into Safe Mode with Internet connection, I can get the blessed thing to work ok.
However, as soon as I restart the computer and out of Safe Mode, into normal use mode, it will not allow me to bring up any web pages, not even a start page which i have set to Google.UK.
At one time I could not even get the silly thing to open Firefox at all.
I have used Firefox for more years than I can remember, not long after it's conception. Never had a problem back in the good old days when you set the browser up with all your add-ons and it never once faltered. Approx 2 years ago is when I started getting all of this clap-trap, and I put it down to Mozilla's interference in ruining a very good browser.
I have other browsers, Edge,Vivaldi and Opera, all working fine. No problems there. I despair completely on the whole business with Firefox.