Oh I lose my windows 7 product key how can I recover it

Windows 7

Windows 7 is a version of Microsoft Windows, a series of operating systems produced by Microsoft for use on personal computers, including home and business desktops, laptops, netbooks, tablet PCs, and media center PCs. Windows 7 was released to manufacturing on July 22, 2009, and reached general retail availability on October 22, 2009, less than three years after the release of its predecessor, Windows Vista.

Windows 7 product key you can generally find behind the DVD cover. For example look this picture.

One of my friend Tutun Bhadra purchase windows 7 ultimate edition few months ago. After two days his younger brothers tore the DVD back cover and throw it in darn.
Now he asked to me how I can install the windows 7 next time. I have no product key.

I told to him no problem.

Thank God.

Some free software is available in the market through which we can able to recover windows 7 product key.

My favorite is of two

1. KeyFinder pro
2. MSKeyViewerPlus

KeyFinder pro

This free software from Gearbox
Windows Product Key Finder Professional is a software utility which allows you to find and recover your CD and DVD Product key for Windows or Office programs for the purposes of reinstalling / repairing your Windows or Office setup. Recover your lost key for (Windows) 2000, XP, 2003, Vista, 7. (Office) XP, 2003, 2007.
 Product Features
Retrieve Product Keys for:
- Windows 2000
- Windows XP
- Windows 2003
- Windows Vista
- Windows 7
- Office XP
- Office 2003
- Office 2007

Other Features:
- Quickly save your product keys to a file
- Print your product keys

KeyFinder pro

MSKeyViewerPlus

MSKeyViewerPlus is a software utility which allows you to find and recover your CD and DVD Product key for Windows or Office programs for the purposes of reinstalling / repairing your Windows or Office setup. Recover your lost key for (Windows) 2000, XP, 2003, Vista, 7. (Office) XP, 2003, 2007.