Y'know, if you have a friend with a laptop that's compatible with your's, then try switching the hard drives around (only takes a screwdriver and a little gentle pulling). If you still have the same problem on your computer with your friend's HD, then it's a hardware problem.
Note: this will NOT work unless both HDs are from laptops. I have done this twice in the past, and it's invaluable information.
Good luck! I wish you the best!
