Have you ever accidentally deleted your 'Show Desktop' icon from the Quick Launch bar? Show Desktop is not an ordinary shortcut and you cannot restore it in normal ways.

To restore your 'Show Desktop', you must open your 'Notepad', and enter or copy the following content:

[Shell]
Command=2
IconFile=explorer.exe,3
[Taskbar]
Command=ToggleDesktop

Save the file as 'Show Desktop.scf' and then copy this file or save it to C:\Documents and Settings\[User Name]\Application Data\ Microsoft\Internet Explorer\Quick Launch. You must replace the [User Name] with your real user name.

Funny experiment: Change IconFile=explorer.exe,3 to IconFile=explorer.exe,4 and save the file to see the result.