The first thing I would check...all connections to/from the drive. Seems routine, but I must confess...it's my biggest failing when I think I have HD problems.
If the drive is an IDE/PATA drive connected inside the computer...check the jumper setting on the drive. If you have it connected to the end connector, the drive should be set as either Master or Cable Select, both work. If there is another drive on the middle connector, then it's jumper must be also set to Slave or Cable Select...but it must be the same pair (CS/CS or Master/Slave) of settings for both drives.
If the drive is a SATA drive, ignore jumper settings.
Next, I would check the BIOS recognition of the drives (all drives) properly.
If all drives are properly recognized in the BIOS and all connections are solid, then I would take a look in Disk Management, to see what it displays for that drive. If the drive shows up in DM as properly partitioned and with data on it...that's good. If it shows up there as a blank slate, you have problems.
Let us know what these few steps indicate and we can go on.
Is there another computer system available to you...to possibly connect this drive to?