One of the first screens you'll see will ask you to enter your product key so you can “Activate Windows.” However, you can just click the “I don't have a product key” link at the bottom of the window and Windows will allow you to continue the installation process.
Can Windows be activated without product key?
If you have a digital license for your device, you can reinstall the same edition of Windows 10 on this device without entering a product key. Make sure that Windows 10 is activated before you try to reinstall it. To find out, select the Start button, and then select Settings > Update & Security > Activation .
How long can I use Windows without product key?
Microsoft allows users to download, install and use the operating system indefinitely without having to enter a valid product key or digital license. Additionally, you can use an unactivated Windows 10 without any restrictions for one month after first installing it.
What happens if you don't have a Windows product key?
Even if you don't have a product key, you'll still be able to use an unactivated version of Windows 10, although some features may be limited. Inactivated versions of Windows 10 have a watermark in the bottom right saying, “Activate Windows”. You also can't personalize any colors, themes, backgrounds, etc.