At any given point in time, I'll usually have about 10+ windows open on my computer.  So when I need to access something on my desktop, which is quite often; I'll hit the show desktop icon to quickly minimize all the windows.  Problem is, my show desktop icon was missing.  Its not a normal program shortcut, so you can't just copy and paste shortcuts as you normally would with a program.  After a bit of googling, I was able to find a quick way to get it back.  Here's how:

 1.  Click Start,  then Run...  The Run Dialog should appear.
 2.  In the textbox, paste the following command: regsvr32 /n /i:U shell32.dll
 3.  Your show desktop icon should be as good as new.