HD should be in a U-shaped bracket. There is a screw at the front of the bracket (HD connector end) underneath the connectors, remove that screw and the bracket can be lifted out, then you'll see how to remove the HD from that bracket. (That U-shaped bracket allows you to add (stack) a 2nd HD very easily) Just set the jumpers as a Slave on the added HD and attach both the second ribbon connector and a power connector, and start the Mac. Voila! more space!