Dell Dimension V400 Service Manual page 48

4-4 Dell Dimension V xxx and V xxx c Systems Service Manual
lock tab into its fastener, and press down on the front end of the beam until
it snaps into position.
4. Position the cover on the chassis approximately one inch back. Slide the
cover forward until it locks into place.
5. Tighten the cover-mounting thumbscrew on the back of the chassis.