He opened CMD as an administrator and typed in the command: slmgr /ipk <product_key> . He replaced <product_key> with the key he thought he had, but the response was: "Error: The product key you entered is not valid."
The screen flickered. A small Windows Script Host box popped up: windows 10 cmd activation
John learned a valuable lesson about the importance of keeping track of his product key and using CMD commands correctly. He also appreciated the wealth of information available online, which helped him troubleshoot and resolve the issue. He opened CMD as an administrator and typed
He closed the CMD window.