How do I show and hide the different toolbars?

Most toolbars can be shown or hidden depending on your needs. To show or hide a toolbar, right-click on an empty section of the Tab Strip and check or uncheck it in the pop-up menu.

   Menu Bar: This toolbar at the top of the Firefox window contains the browser menus (File, Edit, Help, etc.). On Windows Vista and 7, the Menu Bar is hidden by default, and its features are contained in the Firefox button. If the Menu Bar is hidden, you can temporarily show it by pressing the Alt key. 

   Tab Strip: This is where your tabs are displayed. You can't hide it.
   Navigation Toolbar: This toolbar contains your web site navigation buttons, the Location Bar, the Search Bar, the Home button and the Bookmarks button.
   Bookmarks Toolbar: This toolbar contains your Bookmarks Toolbar Folder bookmarks. For more information, see Bookmarks Toolbar - Display your favorite websites at the top of the Firefox window. On new installations of Firefox, the Bookmarks Toolbar is hidden by default.
   Add-on Bar: This toolbar at the bottom of the Firefox window contains buttons associated with your extensions (if they are made available by the add-on developer). See The Add-on Bar gives you quick access to add-on features for more information. 

Toolbars - win1 How do I customize or rearrange toolbar items?

   Right-click an empty section of the Tab Strip and select Customize.... The Customize Toolbar window opens.
   Change the toolbar items as necessary. For an explanation of what each item does, see Customize navigation buttons like back, home, bookmarks and reload.
       To add an item, drag it from the Customize Toolbar window onto the toolbar where you want it to appear.
       To remove an item, drag it to the Customize Toolbar window.
       To rearrange an item, drag it to the spot where you want it. 
   When finished, click Done. 

Toolbars - win2

Try it out: Experiment with different arrangements. You can always restore the default toolbar settings by clicking Restore Default Set in the Customize Toolbar window. Icon appearance options

There are additional options to change the appearance of your toolbar icons at the bottom of the Customize Toolbar window:

   Show: From the Show dropdown menu, you can choose what to display in the toolbars: icons, text, or icons and text together. By default, Firefox shows icons only.
   Use Small Icons: Check this option to make the toolbar smaller. 

How can I add extra toolbars?

   Right-click an empty section of the Tab Strip and select Customize.... The Customize Toolbar window opens.
   At the bottom of the Customize Toolbar window, click Add New Toolbar. The New Toolbar window opens.
   In the New Toolbar window, enter a name for your toolbar and click OK.
   Add items to the toolbar as described above. If you don't add any, Firefox won't create your toolbar.
   When you're finished adding items, click Done. 

Your new toolbar appears below the Navigation Toolbar.

Try it out: Make a new toolbar. You can always remove extra toolbars by clicking Restore Default Set in the Customize Toolbar window. I have missing toolbars, unwanted toolbars or toolbars that get reset

Thank you Mohammed.Samad. Restoring the menu bar appears to have solved the problem.