Sometimes we accidently delete the Show Desktop icon in the Quick Launch menu.You can manually recreate it by creating a file called “Show Desktop.scf”.

Open Notepad,and type in the following :
[Shell]
Command=2
IconFile=explorer.exe,3
[Taskbar]
Command=ToggleDesktop

Save this file as “Show Desktop.scf” by selecting the “Save as” type as All Files –to prevent the file being saved as “Show Desktop.scf.txt”.
Now all you have to do is drag this file to the quick launch toolbar and your show Desktop Icon is restored.Another way is to use the Regsvr32 command .Go to Start>Run and type in “regsvr32/n/i:U shell32.dll”.This should restore the Show Desktop icon.