What is the Motherboard.?
What is the Harddrive.?
How is the harddrive attached? EIDE or SATA?
Is are the drives detected at POST?
If they are EIDE: What are the Settings, if there are optical drives on the same cable, are they set to slave and the HD set to master?
Try the HD on the cable alone, Disconnect the other HD (If you have one) or the other Optical Drive (If you have more than one). If you have one HD and one Optical Drive, put them on Separate EIDE Channels and change jumpers so they are both Master.