Restoring the ‘Show Desktop’ button

This was harder than I expected. Here’s the trick: create a new text file in Notepad, and copy this into it:

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

Save the file as “Show Desktop.scf” (enter the quotes to force notepad to save it as an .scf), then drag it to the Quick Launch bar.