Hit the Alt key (Cmd for Mac) to show the Menu bar, then open View > Toolbars and select Menu bar, so it has a check-mark.

i am not sure what i hit but my browser bar is gone along with my favorites and home icon at the top of the window

well i HAD the same problem and it worked just fine with "alt" thx! (didn't loose any favorites or bookmarks :P )

same problem, but I have windows 7.....

Thanks that makes so much sense, and it worked great!

Same problem here, I have no Firefox toolbar, no bookmarks, no matter how many times I restart Firefox.

In Firefox 3.6 and later on Windows you can hide the menu bar via "View > Toolbars" or via the right click context menu on a toolbar.

Press F10 or press and hold the Alt key down to bring up the menu bar temporarily.

Go to "View > Toolbars" or right-click the menu bar or press Alt+V T to select which toolbars to show or hide (click on an entry to toggle the state).

See also Restore the Menu bar in Firefox and http://kb.mozillazine.org/Toolbar_customization