• If, on Windows, in Firefox 3.6 the menu bar is hidden then press and hold the Alt key down or press F10, that should make the "Menu Bar" appear
• Go to "View > Toolbars" and check-mark "Menu Bar" with a click on it to make that permanent. See Restore the Menu bar in Firefox).
• Make sure that you have the "Navigation Toolbar" and the "Bookmarks Toolbar" visible: "View > Toolbars"
• If items are missing then see if you can find them in the "View > Toolbars > Customize" window
• If you see the missing item in the Customize window then drag it back from the Customize window onto one of the toolbars.
• If, in "View > Toolbars > Customize", you do not see that item then click the "Restore Default Set" button

See also:

• http://kb.mozillazine.org/Toolbar_customization

Thanks. Unfortunately, the alt-F10 commend didn't work, so I can't access the "view" option.

It says Alt or F10 and not both keys simultaneously. If you hold down the Alt key the the menu bar should appear. You can also press F10 to make the menu bar appear immediately.