Dell Dimension 4500C (Japan Only) - Manual (Page 91)

Adding Parts 91
9 Align the notch on the bottom of the module with the crossbar in the
connector.
NOTICE: To avoid damage to the memory module, press the module straight
down into the connector while you apply equal force to each end of the module.
10 Insert the module into the connector until the module snaps into
position.
If you insert the module correctly, the securing clips snap into the
cutouts at each end of the module.
securing clips (2)
connector
memory connector closest
to microprocessor
notch
memory module
cutouts (2)
crossbar