Here is the list of generic keys for various Windows 10 Editions. When you use tools like ProduKey, MagicalJellyBean Keyfinder or a custom script to view the product key, only the generic key is shown and not the key from your previous (Windows 7/8) installation. If you have upgraded to Windows 10 from Windows 7 or 8 using the digital entitlement free upgrade scheme, your system is automatically assigned a generic key during upgrade.
These generic keys work with any ISO or DVD/USB Windows setup media. In that situation, you can use the generic product keys for Windows 10 officially released by Microsoft. Windows 10 Setup – Can’t bypass Product Key input
