Seemingly Irreversible Custom Keyboard Shortcut I have a late 2010 Apple MacBook (If that matters) and when I had OS X Snow Leopard installed, I created a keyboard shortcut that I seemingly can no longer reverse.  After upgrading to OS X Lion and now OS X Mountain Lion the shortcut is still carried over.

The keyboard shortcut is: whenever I click the 'fn' key, it will 'show desktop.'

I have searched all of the 'Keyboard' section of System Preferences to see if I can deactivate anything there.

I do remember that when I made the shortcut originally on Snow Leopard, it could be changed back.

I remember when I had OS X Lion, I wanted to change it, but I couldn't figure out how (like now)

I have tried the 'restore defualt' option in System Preferences > Keyboard, but that didn't work.

If anyone knows how to fix this or even has some sort of guidance to help me try and fix it, it would be greatly appreciated as this is becoming an increasingly inconvenient and frustrating problem.
A similar question entitled "Fn key shows the desktop on my Mac" was posted in July 2012 on Superuser, and maybe of help.

https://superuser.com/questions/455603/fn-key-shows-the-desktop-on-my-mac

(If my answer is more appropriate as a comment, please convert it to one)