How often:
Generally you should try to clean your computer every 3-6 months. If you use your computer often and if it's in a very dusty environment then you should clean it sooner, like every 3-4 months. If you use your computer sparingly in a fairly dust free environment you don't need to clean it as often, maybe every 5-6 months.

What you need:

• Screwdriver (to open up the computer case)
• Can of Compressed air (to blow away dust inside the computer)
• Cleaning Liquid: Rubbing alcohol or mild cleaning agent (dish detergent mixed with water...)
• Cotton swabs (Q-tips)
• Paper towel or cotton cloth

Make sure your computer is turned off before you begin the cleaning process!

Notes:

1. A computer on the ground attracts more dust than one elevated on a platform.
2. Static attracts dust. Wiping down your computer with a solution of one half vinegar and one half water will minimize static.