Is your "Show Desktop icon" in XP missing

Click Start->Run
In the "open" box, type "notepad" (without the quotes)
Click ok
Copy the following lines in your new notepad window :
[Shell]
Command=2
IconFile=explorer.exe,3
[Taskbar]
Command=ToggleDesktop

Click "File" in the notepad menu and select "Save As"
Save the file to your desktop as Show Desktop.scf
Drag the new icon from your desktop to your Quick Launch toobar and select "Move here"
If you can't move the new Desktop icon to your Quick Launch toolbar for whatever reason, you can also try the following technique :

Right-click the new show desktop icon on your desktop and select copy
Open Windows Explorer and navigate to
C:\Documents and Settings\\Application Data\Microsoft\Internet Explorer\Quick Launch (replacing with the username for which you want to restore the show desktop icon)
In the right pane of the explorer window, right-click an empty spot and select "paste"
Maybe you don't see the Application Data folder in your Explorer. To see it, you must enable visibility for hidden folders :

In Windows Explorer, click the menu "Tools" and select "Folder Options..."
Click the "View" tab
Under "Advanced Settings", select "Show hidden files and folders"
Click ok