Your answers are pretty much useless IMO. Response #2 is useful information. The only thing I would add is that you could try physically removing the drive but keep it connected. Then use something like the handle of a screw driver to tap on the side of the drive. This MIGHT get the drive rotating if the bearings are the problem.
ONLY tap the side.
Both cables are needed but the power cable is the one you need to be concerned with now to verify the power connector (molex) is actually supplying power. Swap with a known working connector to verify.