Sony VAIO VAIO MicroTower User Manual page 63

Align the DIMM over the socket.
Firmly insert the bottom edge of the DIMM into the socket.
Press evenly against the DIMM's upper corners. The end latches snap
into position automatically.
Reinstall any add-in cards or components you removed.
Replace the diskette drive and cover panels, as described on page 67
to 70.