So - one lingering problem. I always used Firefox as my home page, but at some stage before these problems, I suddenly ended up with Bing
So I worked out how to change it back to Firefox, so far so good. But if I open a second tab, it's Bing and also, on the Firefox page, my search engine is Amazon, so anything I put into search comes up as something on Amazon
I really don't know what to do about that!
I think some of this started when SIL gave us a torrent url which he uses regularly and successfully, but seemed to dump all sorts of crap on my laptop, so I stopped the download and removed as much as I could find. Certainly the Bing thing dates back to then, a few weeks ago. I must say the Malwarebytes appears to have got rid of so much rubbish and things are moving better generally.