The ticket ID is #557369 but it looks as if it was closed
One of the pop-ups is as follows:
<female voice saying "threat has been detected">
Threat Blocked
Object
https://131.253.61.96/Infection
URL:Mal
Process
C:\ProgramFiles (x86)\Mozilla Firefox\firefox.exe
Report the file as a false positive
The only option it gives me is to Run Smart Scan which I have done but the scan returns the same results each time - all positive, no problems.
I also just got a pop-up for Word 2016. They pop-up about every 30 seconds.
I feel inclined to report them as false positives but would prefer to be told that it is safe to do so.
The links mentioned above don't appear to relate to my problem - there is no mention of poorly rated add-ons. I'll install software obtained from links on a forum only as a last resort.