Paul has a Dell XPS series desktop that's about six years old. He's getting a message that it's not available for a Windows 10 upgrade. Leo says that could be. Although that computer is more than capable of running Windows 10. Leo advises updating the motherboard drivers. First he should roll back to Windows 7. Then he can update the drivers, run the compatibility checker, and then try installing again.
The chatroom says there are workarounds, but Leo is nervous about working around the issue. It's far better to be patient. Sooner or later drivers will be available to upgrade, and there's no real hurry. Paul has a year to upgrade for free.