After my Answer Line post How Do I Regain 'Show Desktop'? appeared in the April print edition of PC World, Jim Stubchaer wrote to remind me that you don't actually need the Show Desktop icon. There are two other ways to minimize all of your windows and show the desktop hiding behind them.
Probably the easiest way is to press WINDOWS-d--in other words, hold down the keyboard's WINDOWS key while you press d. The WINDOWS key is between the CNTL and ALT keys on most keyboards, and is marked with a Windows logo.) The same key combination will also restore your windows.
If your keyboard doesn't have a WINDOWS key, or if you simply prefer the mouse, right-click an empty space on your Taskbar and select Show the Desktop. To restore your windows, repeat the process; only this time, the menu option will be Show Open Windows.