Sometimes these things happen, if you have accidentally hidden the menu bar in Internet explorer 7 or 8 there is a way to restore it back. If just hate the menu bar and want to hide the same steps apply.
After you open IE follow these steps :
Do one of the following:
•In Internet Explorer 8, click the Tools button, point to Toolbars, and then click Menu Bar.
•In Internet Explorer 7, click the Tools button, and then click Menu Bar.