Click on the Start menu and type "cmd" in the search bar.
Right-click on "Command Prompt" and select "Run as administrator".
In the Command Prompt window, type the following command and press Enter:
slmgr.vbs -ato
Wait for the activation process to complete. You should see a message indicating that Windows has been activated successfully.
If the above command does not work, you can try the following command:
slmgr.vbs -rearm
Forcing Windows activation is only legal if you have a valid license key for the operating system.
If you do not have a valid license key, you should purchase one from Microsoft or an authorized reseller before activating Windows.