If online activation does not work, use the automated phone system to activate Windows.
You must activate Windows within 30 days of installation. Activation helps verify that Windows on your computer is genuine.
Activate using the Internet
When you begin the activation process, Windows tries to detect an Internet connection. If one is found, you can activate online.
1. Select the Start button, then select Settings > Update & security > Activation.
2. If Windows detects an Internet connection, click Activate Windows online now. Administrator permission required If you’re prompted for an administrator password or confirmation, type the password or provide confirmation.
3. Type your Windows 10 product key when prompted, click Next, and then follow the instructions.
Activate using the Telephone system
1. Press the Win+R keys to open Run, type SLUI 4, and click/tap on OK. (Typing SLUI.EXE 4 into the search bar also works.)
2. Select your country or region, and click/tap on Next. (see screenshot below)
3. Call one of the provided phone numbers for a Microsoft Product Activation Center. It would be best to call the toll free number. (see screenshot below)
4. Enter the Confirmation ID and then click on 'Activate Windows.'
5. You're all set! :)