Notebook computers have external vents on the side, back or bottom of the case where the fan expels warm air to keep the computer operating at a safe temperature. Excess dirt can block these vents. Use any of the following methods to remove excess dust from the vents on the notebook:
Clean the vents with a clean, soft cloth or cotton swab.
Vacuum the vents with a handheld vac or dusting attachment on a household vacuum cleaner.
Blow the dust out of the vents using compressed air (available at most computer and electronics stores). Be careful to angle the air flow away from the computer to ensure you do not blow the dirt further into the computer case.
Use the following guidelines to ensure you are using the notebook in the recommended environment and prevent a build up of dirt around the vents:
Regularly wipe the exterior of the notebook case with a clean, soft cloth to prevent a build-up of dust that could interfere with air circulation of the cooling system.
Provide adequate air circulation to prevent internal heat buildup.
Leave a space of at least 8 inches behind the back panel of the notebook.
Do not place your notebook on porous surfaces such as rugs or blankets, or near materials such as curtains or draperies that may block the ventilation slots.
Do not cover the computer or adapter with clothing or blankets when the computer is turned on as covering these components may cause an additional heat build-up, resulting in damage to your unit.
Do not use the notebook computer on your lap for an extended period of time; extended contact with the computer or adapter may cause discomfort.
good day mr. doug (it's a day in here while I wrote this message) about the 3rd alternative in your answer which saying "Blow the dust out of the vents using compressed air, and bla bla bla..." how to blow it out of my VAIO safely ? is it necessary to remove and unscrew all cover (including RAM cover, etc)? anyway, my vaio is VPCCW25FG. thanks in advance for your upcoming answer. Ade C ******.