NEC POWERMATE PROFESSIONAL - SERVICE MANUAL 05-1997 Service Manual page 107

CAUTION: A slot cover can damage the
system board or any option board if it drops into
the system. Take care not to drop the slot cover
when removing the screw.
If the slot cover does fall into the unit, remove it
before replacing the cover.
4. Hold the board by its edges and insert it into the expansion slot. Align full-size
expansion boards with the guide rail at the front of the system unit.
Press the board firmly into the expansion slot connector. You might have to gently
rock the board from side-to-side to seat it into the connector.
Figure 3-6 Removing a Slot Cover
Option Installation 3-9