The Toolbar was in Internet explorer and appeared under the Address line. When I looked at View, Toolbars it showed "Fork Show" ticked. Removing the tick removed the toolbar temporarily but it returned.
In the end I entered a search on the Fork Show toolbar and it turned out to be a toolbar for a search engine (Lop.com) which had been installed.
On Add / Remove programs it can variously be shown as Lop.com, LOPSEARCH, Window Searching, Window Active, Browse Enhancer or Ultimate Browser Enhancer. Not a sign of Fork Show anywhere!!
I was able to download a universal uninstall program from their website so it is no more.
This thread is now locked and can not be replied to.