SterJo Key Finder is a tiny, portable tool which will quickly locate and display product keys for Windows, Microsoft Office and many other applications (various FIFA and Medal of Honor editions, ACDSee, various Adobe apps, AutoCAD, assorted Cyberlink and Elcomsoft products, and the list goes on).
This can be very useful if you've lost the original keys, perhaps by misplacing the program disc case - if you don't have the key, you may not be able to reinstall your software later.
SterJo Key Finder makes it easy to recover this information, though - just launch the program and any product keys it finds will be displayed right away.
You can then manually note any keys of interest. Right-click a particular key, select Copy Product Key and it'll be copied to the clipboard. Or click File > Save As and you can save your keys as a text file for easy reference later.