Replace your Zune HD's lower rear panel.
Remove the four Tri-Wing screws securing the upper rear panel to the inner chassis.
Slightly rotate the top edge of the upper rear panel away from the Zune.
Lift the upper rear panel straight up off the black plastic lower rear panel.
Insert a small Zune opening tool into the gap between the logic board and one side of the black plastic lower rear panel.
Carefully twist the Zune opening tool to pop the lower rear panel off the clips attaching it to the Zune.
Carefully slide the lower rear panel away from the Zune.