It may have failed.
Is this a new drive? - or a previously working drive from another computer? - or a drive that was working in this computer.
Have you just fitted it? - have you made any changes at all with your drives?
How have you set the jumpers on it? - what is the jumper on the Master drive set to? - is this a slave on the Primary channel to another hard drive - is it a Slave on the Secondary channel to an Optical drive?