2) Unplugging the drives: Looking at the unit from the front, the DVD drive is on the left and the hard drive is on the right, notice that the hard drive has a standard four wire molex plug while the DVD drive had a custom power plug (the wires are usually colored yellow). Unplug the molex plug from the hard drive while leaving the DVD drive’s power connector plugged in. You will also notice that each drive has a data cable (these are usually grey in color and very flat), unplug the data cable from the DVD drive.
3) Plugging in the PC DVD drive: Place the PC DVD drive on top of the original XBOX DVD drive, plug in the data cable that you removed from the original DVD drive. Take the standard Y power connector, plug one end into the power cable coming from the XBOX. There are two connectors left, one for the hard drive and the other one for the PC DVD drive, plug both of them in. We are now ready to plug the XBOX in and boot it up.
Why do we need to plug in the dvd drive?