The below steps show how to restore the Show Desktop shortcut if it has gone missing;
1) Open Notepad and paste in the below;
[Shell]
Command=2
IconFile=explorer.exe,3
[Taskbar]
Command=ToggleDesktop
2) Save the file as “Show Desktop.scf” – remember to use the quotes else notepad may save it with a .txt extension.
3) If you want the shortcut back on the quick launch bar either drag it there.