Which one? The Menu Bar or Navigation Toolbar? I accidentally hid my Menu Bar earlier this evening. I clicked Alt to bring it back up, then went to View, Toolbars, and checked Menu Bar where I had accidentally unchecked it. Hope it's something as simple as that for you.

Thanks that fixed it! Spent several hours looking for this answer in FAQs ?'s etc without success

See also:

• Restore the Menu bar in Firefox
• http://kb.mozillazine.org/Toolbar_customization

This was the best, thank you!