With the CD cover open and the side off, you will see the drive mechanism. The old belt has stretched and lost elasticity over time and is now slipping. That is why the cover will not open without assistance.

You can pull the old belt off the larger wheel on the outside and it will come free of the drive wheel.

The old belt is a square belt you will be replacing it with a round Danco #39 "O" Ring.

Place the "O" Ring in the centre of the large driven wheel and use a Spring Hook similar to the one shown to push the opposing side of the "O" Ring in and over the drive wheel, pull the spring hook down to disengage it and the "O" Ring will now be in place ready to work!