I am using the newest version of Firefox and I occasionally get a window that is displayed I don't wish.  As an example I get a full Firefox ( takes the whole screen ) that I have a virus and says unless I call a certain number my hard disk drive will be formatted.  The only way I can get rid of it is to reboot my Ubuntu 16.04.  Does anybody know of an application that will run in the background and kill this window automatically when it takes over my computer.  
Background process to automatically kill unwanted popups
firefox