Maybe you've picked up some kind of Spyware/adware/trojan which is causing this. Try using Ad-aware/Spybot/A-squared to see if that is the case. If not try a fresh re-install of Firefox remembering to uninstall it first. This may solve the problem.
This thread is now locked and can not be replied to.
Sniper Elite 4 review: Headshotting Nazis has never felt so good
1995-2015: How technology has changed the world in 20 years
The Fresh New Fonts of 2017
WWDC 2017 dates: How to get WWDC 2017 tickets, when is WWDC 2017 and more details announced
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.