Restore the Show Desktop icon to Quick Launch bar

To restore the missing Show Desktop icon to the Quick Launch bar, try any of these methods:
Method 1:
Click Start, Run and type the command regsvr32 /n /i:U shell32
The Show Desktop SCF file should now be available.
Method 2:
Click Start, Run, and type Notepad. Type the following contents into the document.
[Shell]Command=2IconFile=explorer.exe,3[Taskbar]Command=ToggleDesktop
Save the file as "ShowDesktop.SCF" [with double-quotes]. Drag the file to the Quick Launch area.
Method 3:Search for the file named Show Desktop.scf in your computer by logging in as administrator. Every user profile has a copy of this file. Copy it to your user profile path here:
%Appdata%\Microsoft\Internet Explorer\Quick Launch
Type the above path in Start, Run dialog.