As the others have pointed out. Make sure your SATA cable is connected (they only go in one way) on both ends (motherboard and HD). Also, make sure its in SATA or SATA1 on your motherboard. Sometimes that doesnt matter but its best to do that to rule that out as being the cause.
Another thing to look at is the power cable. And again, it goes in only one way. It will be the longer plug than the SATA plug.
This drawing may help you out:
Lastly, in BIOS, make sure it has your hard drive name like so:
Where ST3888110AS is WDxxxxxxxx.
Hope that helps!
David