Please perform the following steps as shown in the pictures below.
Note: If only one Memory is used on the computer you are servicing, the card must be installed in SLOT-0 ([a]), but not in SLOT-1 ([b]).
When installing: Insert the notched end of the Memory into the socket. Press the Memory firmly, and pivot it until it snaps into the place. Make sure that it is firmly fixed in the slot and does not move easily.