It runs out you can't just move your old drive with windows from one MoBo to another. You have to reinstall Windows 10!

I figured that out the hard way, spent hours googling the problem and hooked/inhooked drives, updated Bios, changed Bios stuff, but no one said you had to re-install Windows.
When you search for drive showing up in Bios but not booting, there is a whole bunch of site showing you how to fix that, but it seems they all assume you had already installed/reinstalled Windows on your drive in your brand new board and it's a goose chase.