Compaq Deskpro 2000 Series Reference Manual page 85

5. If you are installing an expansion card on the side of the
expansion riser board that has three expansion slots, you
need to remove only the retaining screw and the expansion
slot cover.
If you are installing an expansion card on the side of the
expansion riser board that has two expansion slots, follow steps 2
through 4, then skip to step 8.
Removing the Retaining Screw and the Expansion Slot Cover
-9
Reference Guide 5