Thanks for joining the Chipset community.
Is this new installation?
Are you setting up any RAID level?
If this is a new motherboard with and old hard drive, it might not detect bootable portion because previous operating system is already installed on the old disk, therefore, you need to re install the system.
I figured it out - new computer was set to boot with UEFI. I changed it to "legacy" and it recognized the old drive.
I am glad this computer issue was addressed.