I recently added a new SSD boot drive to my computer, and performed a clean install of Windows 8 on the drive. Before installing Windows, I switched from IDE to ACHI in the BIOS. The previous boot drive was an HDD set to IDE.
After Windows 8 was installed on the SSD, I reconnected the HDD to the motherboard. The HDD is visible as a SATA connection in the BIOS, but it's no longer a boot option, nor is it visible in Windows Device Manager. How can I get my secondary HDD working again?
For that device to be bootable, you would have to adjust BIOS settings. For that device to be visible, you may need to wipe it and initialize the disk within disk management.
If I were you, I would disconnect the HDD and plug it into another computer via a USB to SATA adapter. Then, migrate any files you need to save and wipe the hard drive. Then test to see if it's visible on your original PC.