How to uninstall Norton Safe Search as default search engine in Foxfire

I inadvertently said OK to install Norton Safe Search as the default search engine in a recent Norton 360 upgrade.  The search engine - powered by Ask.com is a little worse than useless INHMO, it is circular and rather than finding relevant URLs, it just pops up more searches or advertisements. 

I've followed the instructions in Firefox to set my default search engine back to google, but to no avail; when I click new tab, a new Norton Safe Search window appears.  How do I get my default google window back with my most frequently visited URLs?

I've tried unsuccessfully to search for solutions in this forum.

Versions Norton 360 22.5.2.15, Windows 7, Firefox 39.0.3

 

John v