Toshiba Qosmio F20 (PQF22) - Manual (Page 21)

User’s Manual xxi
General Precautions
To prevent possible overheating of the CPU, make sure the cooling fan’s
air intake is not blocked. The fan draws in air by creating a vacuum. If the
fan is blocked, it could cause the CPU to run at a lower performance level
or cause the computer to shut down. Loose items such as notebook and
tissue paper, plastic wrappers, or other similar materials can block the air
intake, preventing air from reaching the CPU. Do not use the computer on
surfaces with objects that can be drawn in by the cooling fan.