solution #1.
Open and copy the scripts below into notepad
[Shell]
Command=2
IconFile=explorer.exe,3
[Taskbar]
Command=ToggleDesktop
Save the file as “Show Desktop.scf ”. Note: there is an space between the ‘show’ and ‘Desktop’ words
Open the ‘%Appdata%\Microsoft\Internet Explorer\Quick Launch’ and copy the “Show Desktop.scf’ file into it.
solution #2.
regsvr32 /n /i:U shell32.dll
Note; both solution 1 and 2 are usefull in some OS, however, solution 2 is only useful for XP system.