How you activate Windows 10 after reinstalling it depends on how Windows 10 was originally installed on your device.
If you activated your free upgrade to Windows 10 or bought and activated Windows 10 from the Windows Store, you have a digital entitlement for your device. This means you can reinstall the same edition of Windows 10 that your device has a digital entitlement for without entering a product key. During reinstallation, if you’re asked to enter a product key, select Skip. Your device will automatically activate online after the installation is complete.
If you previously installed and activated Windows 10 using a product key, you’ll need to enter the product during the reinstallation.Starting with
Windows 10 Insider Preview Build 14371, you can link your Microsoft account to the Windows 10 digital license (formerly called digital entitlement) on your device. This can help you reactivate Windows using the
Activation troubleshooter if you make a hardware change later, such as replacing the motherboard.
This tutorial will show you how to
activate Windows 10 online or by phone with a product key on your PC.
You will need an
Internet connection and must be signed in as an
administrator to activate Windows 10.
You will need to
activate Windows before you can personalize your PC.[/warn]
Depending on how you got your copy of Windows 10, activation will use either a digital entitlement or a 25-character product key.
Digital entitlement is a new method of activation in Windows 10 that doesn't require you to enter a product key.