I have a PC running Window 7 Pro. When I opened my Firefox browser I discovered Bing has hijacked my browser (from Google) as the default search engine. But only when I launch Firefox. If I open a new tab while the Bing search engine page is open, it opens in Google. And it remains in Google for any additional new tabs I open. But if I close all tabs and launch Firefox again. Bing opens. How do I get Google back upon launch and remove Bing 100% ?