Maybe some system details? laptop/server? MB, cpu,memory, did they ever work? what harddrives sata/ide/ botting from disk, usb, network ?
Assuming it's a new build, sata harddrives, swap the sata calbes to different connectors - are any connectors recognizes ? Since it's two drives it's unlikely its the drives, but can you check them in another system? Is this a new MB or did it work prviously? Some MBs drive SATA ports with two different chips (e.g. 6gbit and 3gbit sata, or when the integrated sata doesn't give enough ports) try to swap to ports you know are from different chips. Did you reset bios? Did you try achi vs. legacy mode in sata port def. Did you try just one drive? Then just the other ?