Thanks again for all your input. I checked, (and removed), some programs that were booting at startup. Because, by now, computer wouldn't let me into ANY website to upload malwarebytes, started a windows 'update' session. (Hadn't done this for a while).

Computer now 'seems' ok, but I don't trust it, so am going to upload and run malware bytes, plus carry out a few of the other suggestions made by some of the posters on this thread

Thanks again