Hard drive not being recognized by BIOS (Motherboard is an ASUS P5K)

I have been putting together a new computer, and once I started it I noticed that BIOS for the motherboard (an ASUS P5K) didn’t detect the hard drive. I changed some of the settings to try to fix this problem, and upon rebooting the hard drive still was not being detected. I have even unplugged everything and started from scratch yet the result was still the same. Any help would be appreciated.

Alex