When do you need a Windows 10 Product Key and when don't you?

Microsoft explains when we need the Windows 10 Product Key and when we don't - Complete information about activating Windows 10 is provided

With Windows 10, Microsoft is introducing a new activation system called digital entitlement that allows users to upgrade an older operating system, such as Windows 7 and 8.1, to a new one without necessarily needing a product key.

When the upgrade is complete, the system automatically activates (assuming you're running a genuine version of Windows 7 or 8.1), and Microsoft allows you to install it without asking for a product key anymore.

Windows 10 will be reactivated each time you install it thanks to the digital entitlement system that attaches a Product Key to your system (manual re-activation is required when you make major changes to your computer, such as replacing the motherboard).

1. You upgraded to Windows 10 for free from a legitimate device that was running Windows 7 or Windows 8.1.
2. You purchased genuine Windows 10 from the Windows Store and successfully activated it.
3. You purchased the Windows 10 Pro upgrade from the Windows Store and successfully activated Windows 10.
4. You are a Windows Insider and have upgraded to the Windows 10 Insider Preview build.

Basically, the digital entitlement system works in four cases: This means that even if you bought Windows 10 from the store, you are allowed to install it without the need for a product key.

The product key, however, is needed in the following cases:

1. You purchased a copy of Windows 10 from an authorized retailer.
2. You purchased a digital copy of Windows 10 from an authorized retailer.
3. You have a Volume Licensing agreement for Windows 10 or an MSDN subscription.
4. You bought a new device running Windows 10.

Simply put, if you are a new Windows 10 customer who has just purchased a device running the operating system, you should have a Product Key. This is the traditional system used for other versions of Windows, so you should find the Product Key on a small label that comes with your disc or is located on device .