If you don't see the "Tools" menu or the others (File, Edit, View, etc.), you're probably using the same view I use.
There are two ways to get to this menu, one that always turns it on and one that will briefly make it appear.
To briefly make it appear, press the Alt key. You'll see the menu bar appear at the top of the browser window. As soon as you make a selection from a menu, the bar will disappear again. You can, of course, open it again with the Alt key.
To make it so the bar is always on, click the Firefox button -> Options -> Menu bar. This will toggle the bar on and remove the Firefox button. To remove the menu bar again, click View -> Toolbars -> Menu bar. This will return you to the view you probably have now.
