Dell OptiPlex GX280 - Manual (Page 132)

b. Detach the replacement system board from its mounting plate by removing the four mounting screws from the
heat-sink retention base. Set the mounting plate aside for later installation on the old system board prior to
shipping back to Dell.
c. Install the replacement system board onto the metal tray by sliding the replacement system board forward to
attach the board to the hooks on the metal tray. Install the retention base using the four mounting screws, and
then replace the screw at the front of the system board.
d. Install the mounting plate on the original system board using the retention base and the four mounting screws.