get my keys back 2
Free   
3

You can recover Microsoft Office and Windows serial numbers with Get My Keys Back

produkey

ProduKey

 1.97 - 64 bits
Free   

Recovery tool for operating system serial numbers

winguggle

WinGuggle

 2.4
Free   

Security tool which enables you to find the Windows Vista installation key

sterjo key finder
Free   

For locating all of your installation keys to save in a text file

license crawler

License Crawler

 0.0.38
Free   
1

You can recover licence keys for software installed and operating systems.