Sony PCV-J200 - Manual (Page 52)

VAIO® System Reference Manual 40
Covering an Open I/O Slot
Slot covers prevent air from escaping through the empty hole. If air
escapes, the components inside the computer cannot be properly cooled.
This may damage some components, especially the main processor which
generates the most heat.
1
Slide the tip of the slot cover (removed earlier) between the chassis
and system board.
2
Push the slot cover down until it rests firmly on the lip in the chassis.
All add-in card brackets and slot covers rest on this lip.
3
Replace the screw (removed earlier) to secure the I/O slot cover.