With thanks for assistance - the pop appeared on two occasions about a week apart both times when visiting Ebay and cursor around bottom right hand side of screen.
Have changed downloads so that they are saved on desktop (Chrome). All I get is the notepad icon at bottom of screen no red/blue icon as in your reply so can't do the fix etc.
There's no popup ad for iphone - I originally posted here because when I did the scans with the aforementioned software none of them caught anything and want to be sure computer is safe. I have avoided Ebay as that's where I was both times the ad appeared.
This says solved????? Am I to understand that my computer is virus/malware free?? And can you shed any light on why the pop ups happened if the software caught nothing??