I am running Windows 10. I have been running Firefox for years without having this issue but after the most recent update the browser starts up with my PC. It goes so far to start up and launch itself before I have even signed in to my Windows profile on my PC. If I leave my most recent tab on any web page that has audio it will be playing while I am looking at my Windows sign in screen. It is NOT on the list of programs that start up with my PC so I can not fix this through "msconfig", though it is now consolidated with task master. I can not find an option within Mozilla's setting to stop it from starting up with PC.