As much as I understand the key VK7JG-NPHTM-C97JM-9MPGT-3V66T is a generic general key which Microsoft mentions online as well. It's not a license activation key, it can only uses for example when you upgrade the version and can’t activate Windows 10 after install.
Now enter the Windows 10 Pro product key: VK7JG-NPHTM-C97JM-9MPGT-3V66T.Note: Make sure your work is saved and all applications are closed on your computer before starting the upgrade
Execute the Upgrade Command: In the Command Prompt window, type the following command and press Enter: slmgr /ipk VK7JG-NPHTM-C97JM-9MPGT-3V66T (This is a known default key, but its success isn’t guaranteed).