1
If you are experiencing an activation error, what happened on your PC before Windows was not activated.
2
Where did you get your Windows licence was that pre-installed on the PC or did you purchase a full retail Windows licence from Microsoft or from a 3rd party retailer?
Or is your Windows licence based on a previous Windows 7 or 8 licence?
3
Download the free ShowKeyPlus app from the Microsoft Store.
Please provide a screenshot of that app window and please hide any product key in the screenshot.