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However, people don't tend to think about the fans in their computers. They get dirty as well. They also get loud and inefficient when this happens. When your desk fan suffers like this, you're only a little inconvenienced. When your PC fans suffer like this, you're looking at possible (probable) hardware damage.
It's very important to get a can of compressed air (which you actually need a valid ID to purchase in MA! Guess kids were getting high off it too much...) and open the case (after having properly turned your computer off and unplugged it!) and blow the crap out of there! I suggest doing this every four to six months.
Other tips, keep your PC off of the floor, especially if you have rugs, and PARTICULARLY if you have pets. Dogs, cats, etc. wreak havoc on PC fans. Fish and snakes, only if you stuff them into the fan physically...
How many of you do this on a regular basis? Don't lie to me, I'll find out.