You don't say which browser you are using to access the internet. If it is Firefox click on the orange tab in the top left hand corner, go to Options (don't click on it but wait until it expands with another box to the right) - You will see a list of things which are ticked - make sure you have Menu bar ticked. There is another way if you don't want to see these permanently at the top - click on the blank space above the address bar - that is right at the top of the browser - and then press the "Alt" button (the one to the left of the space bar on your keyboard).
In Internet Explorer it may be nearly the same thing.
First, open your Internet Explorer browser. Click on the Tools menu, located in the upper right hand corner of your browser window. When the drop-down menu appears, select Menu Bar. You should now see the Menu Bar displayed in the toolbar section of your browser window.
If you also mean that the command bar is missing.
Right click on an empty space on the toolbar, and click on Command Bar to check it. OR
Click on View (Menu bar), Toolbars, and click on Command Bar to check it.
Hope this helps you.