I clicked on 'Change product key' and entered my valid VLSC Windows 10 Professional key.

The activation status was: 'Windows is activated with a digital license' I almost immediately went into the Activation section of Control Panel to input my product key. At no point do I recall seeing an option to enter a key, to select the version of windows, or anything else that seemed relevant to my problem. I downloaded the Media Creation Tool, created a Windows 10 USB installation device, and I reinstalled Windows 10. The world's largest software company (Microsoft) can't write an operating system that permits this, and I was told that I needed to reinstall the operating system. I called the VLSC and they told me that the installation from HP could not be upgraded. Check the product key and try again, or enter a different one. The error I receive is 'The product key you entered didn't work. I tried inputting the VLSC key on the factory installation by changing the product key. I also have valid VLSC MAK (not KMS) keys for our Active Directory domain / Microsoft Windows 10 Professional. I have a new HP PC (super nice Spectre 13 inch 2-in-1!!) that came with Microsoft Windows 10 Home.

Surface pro 3 wont update