Do you see them listed on boot up? You could try seeing if they get listed if you set your SATA RAID / AHCI Mode to AHCI or/and SATA Port0-3 Native Mode to enable in the BIOS.
Are they in the orange SATA ports? Is the SATA limit jumper off for SATA2 support?
Have you tried them in another computer?
Tried other SATA cables or tested them? Using SATA power cables and not adapter and tested to be working with other HDD?