IBM Aptiva Series Hardware Maintenance page 130

Note: 1. When replacing the old riser card with a new one, make sure
that you remove the GND stitch from the old one and reinsert it
to the new one. Please refer to figure 4-18(encircle illustration)
on how to reinsert the GND stitch.
2. To reinstall the riser card, reverse the removal procedure.
Reconnect any adapter card cables that you disconnected when you
remove the adapter cards from the riser card.
Repair Information 4-23