You might have the wrong disk mode set in your BIOS under the 'Integrated Peripherals' menu. Check the disk controller settings in your BIOS. It should read:
OnChip SATA controller: Enabled
OnChip SATA Type: AHCI
OnChip SATA Port4/5 Mode: As SATA Type
IDE, AHCI, or RAID. Refer to your motherboard's manual page 48.
Let us know what it says. Also, which SATA port is the disk connected to (numbered SATA2_0-SATA2_5?)? The top 4 ports are driven by one controller and the bottom 2 another.
Do you have any other drives attached to this motherboard (HDDs or SSDs)? Which ports are they attached to?