I no longer want to throw my computer through a window!

I love you for this. :) I was still running firefox 3 because I hated firefox 4 so much for this problem that I downgraded again. I finally decided to upgrade (version 12 now!) and was really annoyed that it was still just quitting and closing everything instantly when I hit cmd Q, which I really don't like it doing, especially when I hit it by mistake! I changed everything you mentioned on the about:config page, but it still wasn't working. (I'm using a mac...) A previous commenter was right in saying that in preferences, the "when firefox starts" option has to be set to something OTHER than "show windows and tabs from last time". Counter intuitive, but that's how it goes. I set mine to show my homepage, and I got my beloved warning back. :)