How to find CD Key from installed Windows or M. Office

Well, I got a new experience today. I lost my windows's cd case and I need the cd key to re-install the windows on my pc. I just assumed, that the cd key must be stored somewhere in the system, since it is required every time we install windows. So I browsed around and found the answer from this link.

What you need to install on the PC where the windows installed is this program, Magical Jelly Bean. What you need to do next is just installing the program and let the program do the magic. 

I used it to reveal CD Key for my windows and M. Office. 

Hope it can help you somehow, cheers...