Can't authorise after reinstall of Windows and ADE

I reinstalled Windows 10 as a clean install on my PC - the original Win10 was an upgrade from Win8.1 which was itself an upgrade from Win7. After the Win10 reinstall, when I install ADE 4.5.1 and attempt to authorise the computer with my Adobe id, I get an error message saying: "You can only authorize this computer with an Adobe ID that hasn't been previously use to authorize any other computer or mobile devices. Please try again."

How do I fix this?