Remove the 2 black 3.5mm phillips screws from the bottom side of the board.

The hard disk will only be connected by the IDE connector. Support the hard drive with your hand while turning the board over.

Gently, but firmly remove the hard drive from the IDE connector by wiggling back and forth slightly and pulling back toward the side of the board.

If you have made it this far, DO NOT STOP HERE. It's virtually impossible to re-seat the system board correctly without disassembling further. Proceed to the next step!