|Well there are two possibilities.|
1. Your hard drive has failed
2. Your hard drive has not failed but something else is wrong that leads to the appearance of that error.
You could try re-seating the data cable of the drive, or a different cable to eliminate that as a possibility. Apart from that the drive manufacturer will have a diagnostic tool available for download. It is usual to run the diag tool from a bootable floppy or CD to test the drive integrity.
Goin' Fishin' (Some day)