i have lost the address bar and cannot type in web addresses. how do i get the address bar back?
Most probably, you have accidentally turned the Navigation toolbar off.
See this article (the part: I've tried it and I want to go bacl) for steps to activate it again:
Display the Firefox button menu instead of the menu toolbar
Make sure that toolbars like the "Navigation Toolbar" and the "Bookmarks Toolbar" are visible.
Use Toolbar Layout (Customize) to open the Customize window and set which toolbar items to display.