How to Find a Product Key in Registry
When you purchase new software, you have to activate it with a product key. The product key for a piece of software can usually be found on the installation CD or in an email if the product was bought online. If you lose your product key, it can be retrieved quite easily by navigating through Windows Registry.
Click the Start button, type "regedit" into the search bar and press enter. This will launch the Registry Editor.
Click the plus button next to "HKEY_LOCAL_MACHINE," then navigate to "Software" and double-click the folder.
Locate "Microsoft" then double-click then folder to open it.
Scroll through the folders to find the directory that contains the software you need the product key for.
Double-click "Product ID" to see your product key.