Disconnect the hard drive cable from the hard drive using a spudger by gently loosening one side at a time. (Be careful not to pry to hard or you may bend the pins.) You may need to remove a piece of orange tape attaching the ribbon cable to the hard drive.

This is a bit tricky. If you bend the pins, do your best to straighten them using the hard drive cable as a guide.

If you are installing a new hard drive, we have an OS X install guide to get you up and running.