What is the current startup setting?

• Tools > Options > General > Startup: "When Firefox starts":
  "Show my windows and tabs from last time"
  "Show my home page"
  "Show a blank page"

With "Show my windows and tabs from last time" Firefox won't aks when closing a window.

You can also check warn pref on the about:config page.

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue. You can use the search bar to filter prefs and search for warn.

• http://kb.mozillazine.org/about:config

I don't understand. I don't know how to find those things. I need basic instructions for computer dummies (or I probably would have figured it out on my own). It used to ask me before shutting down, but for some reason it doesn't ask now, after a crash earlier today.

What is the startup setting?

You can find an Options button in the "3-bar" Firefox menu button drop-down list. You can find this button on at the right end of the Navigation Toolbar (this is the toolbar with the location/address bar). Alternatively you can tap the Alt key or press F10 to show the Menu Bar and open the Tools menu to access the Options page.

Until today the pop-up would appear and so I wouldn't accidentally shut down multiple tabs in Firefox, and the next time I started up, everything would open up. Now it just shuts down without warning me that I accidentally clicked on shut down Firefox instead of closing a tab--for either one I click on an x and if I'm in a hurry or distracted, sometimes I hit the wrong x. It also lets me know how many tabs I have open. If I have it so that Firefox restores the previous session, is there any way to get that pop-up back? This afternoon is the first time the pop-up didn't um, pop up. I miss that.

If you set to restore the previous automatically then you wouldn't get a confirmation dialog. Only with one of the other two choices you will get the dialog.