Hi All, First, thank you for all your suggestions & help.
For the time being all is working OK.
What did I do......I wish I knew !!!
I read a article in PC PRO July 2016 issue 261, where Antony Dowling writes about how he repairs infected computers.
I ran the ESET scanner (eset.com/us/online-scanner-popup) & Windows Repair Tool from Tweaking.com.
There were pages of info produced, mostly unintelligible.
The repair tool had 47 items to repair but the first seemed to be taking an hour. I left the computer running all night.
I am not convinced it had finished this morning, but I stopped it. I tested my router access... and it worked.
So far all items that matter seem ok.
@ parkdale. I reinstalled Firefox, and it did the same as the other browsers but it did say something about translation, which i now can't reproduce.
@ Stuart. I tried Wireshark, I could not see how to pick out that bit of info, must try again.
Thank you, Malcolm