Check you variant - download latest bios or make sure your running the latest. try another Sata port on the motherboard likely you have sata port 0 - 1 - 2 - 3 but i havent looked at the board manual. It should always pop up in the bios area and so should your hard drives.
If they are not seen on any port what Power SUpply you got 200w? 300w ? could be a low PSU.
Thats all i can think of right now