Sony PCV-L640 - Manuel (Page 42)

VAIO Slimtop™ Reference Manual 28
5 If you do not replace the card or install another add-in card, install a
slot cover over the vacant slot at the rear of the chassis (see
“Covering
an Open I/O Slot” on page 45).
6
Replace the system cover (see “Replacing the System Cover” on
page 25).