I’m back! Did you miss me?
After much hardware shunting, Windows is finally up and running and my backup is being restored as I type. Phew. Ben figured out the below solution during the course of a marathon phone call – thanks, Ben!
For googlers: If your A8R-MVP will not boot from SATA hard drives, resulting in messages that ask you to insert boot media (or it just sits there with a flashing cursor), as well as seemingly interfering with CD-drives, it can be fixed by enabling the SATA boot rom in the bios. Why? Not a clue.