With a lot of windows open it can sometimes be tedious to minimize or close all of the windows. A convenient way to minimize all windows at once is to select the Show Desktop button. Simply click this icon once and all of your windows will minimize to the taskbar.

To be able to use the Show Desktop button, you first have to make sure the Quick Launch toolbar is turned on. To turn on the Quick Launch toolbar, right-click on the Windows Taskbar and choose Toolbars > Quick Launch.

This will make the Show Desktop icon appear on your Taskbar.