First, click on start button and search for Command Prompt and run it as administrator.
And copy paste the following inputs one by one and hit ENTER button each time.
Dism /Online /Get-TargetEditions sc config LicenseManager start= auto & net start LicenseManager sc config wuauserv start= auto & net start wuauserv changepk.exe /productkey VK7JG-NPHTM-C97JM-9MPGT-3V66T
When input the last one and hit ENTER with for a second, the operator will start preparing the upgrade. Don’t turn off your PC. It will restart two times. And your Windows will upgrade successfully.
Watch this tutorial if needed.