I turn my laptop off completely at night. Start it up in the morning and sometimes Facebook, which was the last site I was at, would open up on it's own. Like I never closed out. Can anyone tell me why this happens? There must be a setting for this. Also, after I close out and attempt to go to another site, I get this pop up on my screen that says," Firefox is already running but is not responding. The old Firefox process must be closed to open a new window. So I hit the "close out" then I can get to the other site.

I have Windows 10 and use Firefox