Hey, Derek!
Check if the cable is seated properly in the SATA port. If it is, plug the HDD in a different SATA port.
Maybe you could try with a different SATA cable, because the one you are using might be faulty.
If you reverse the order is it detected properly or not?
Try resetting BIOS to default settings.
I've noticed that your mobo has dualBIOS technology, which means it supports UEFI as well as Legacy BIOS.
I suspect the default settings are set to UEFI, so I'd suggest to boot with BIOS instead.
Keep me posted! Hope this helps!

SuperSoph_WD