From
http://pcsupport.about.com/od/productkeysactivation/ht/windows-7-key.htm
If you're preparing to reinstall Windows 7 you will need to locate your unique Windows 7 product key - also known as the Windows 7 serial or Windows 7 CD key. Normally this product key is on a sticker on your computer or located with the manual that came with Windows 7.
However, if you've lost your product key, all hope is not lost - your Windows 7 key is stored in the registry but is encrypted and not readable, making finding it difficult. Luckily there are several free programs that can help.
Peccavi, February 2013
