Thanks guys.
No recent downloads .... and I always check for unwanted additions and toolbars, so I don't know where it came from.
Strange as the only place where it has appeared was on EF when viewed as a guest (not logged on). No problems on any other sites or EF when logged on.
Had a bit more time and Googled Kontera, and how to remove remedies .... but as usual they want you to download and pay for unneeded software.
Anyway as per methods outlined above, there was nothing to be found under TM processes or in the registry (under given path).
There was a cookie in Ff. for Kontera, and with a search a couple more disguised under different names - all removed, although the Kontera one did keep on reappearing, but only with double-underlines on this thread.
Also excluded cookie acceptance with Ff. (different procedure as outlined for IE), although this didn't stop it's reappearance.
Downloaded a free malware scanner (that I'm familiar with from my other laptop) and ran this ..... but it found nothing Kontera related (but did find a couple of other minor issues).
After all this, it had almost disappeared - only present in the word
"browser" in UTH's post above, for some reason.
Finally ended up installing Adblock Plus add-on for Ff., which now seems to have fully eliminated it.
So ended up with another program and another add-on .... and I was being so careful on cluttering up this (relatively) new laptop.
[I still blame EF
]