Align the DIMM notch with the key in the connector, as in panel 3. This action ensures that the DIMM is oriented correctly. Panel 2 shows an incorrect alignment.
If the DIMM does not easily seat into the connector, verify that the orientation of the DIMM is correct. Never apply excessive force.
Verify a replacement DIMM. See Clear the Fault and Verify the Functionality of the Replacement DIMM.
Verify additional memory. See Verify DIMM Functionality.