When you install Show Desktop, the program puts a small rectangular button on the bottom right hand corner of your screen (at the end of the taskbar) that you can reduce all your open windows when you click it
Also, if you hold the button above the cursor, it will make all the windows transparent, so that you can not reduce your desktop. In other words, Windows 7 lets you do what you can, but using XP.
Program options allow you to change the size of the buttons, while the cursor rests on the window to make the window transparent, and when it does, how much do you want the opacity level?
The desktop is a very useful application for anyone who is still using Windows XP.