Learning to Clean Your Computer Will Save You Money
As always, Safety first. You will need a screwdriver, safety glasses, a can of compressed air, a dust mask or similar ( I usually hold a cloth over my nose and mouth ), and a damp rag.
Turn off your computer, make sure it has powered down completely. Unplug each cable from the unit, and make sure you know what plugs in where. Most things will only plug into the correct place, but make a mental image of how these things go. If this scares you, mark each plug before you unplug them. When you have the tower completely free, remove the side with a screwdriver, there are usually one or two screws on the back to release this cover. Slide it towards the back of the case, and lift the cover off. (Some units have a solid cover that goes completely over both sides and the top)
Once the cover is removed, inspect the interior of the unit, without touching anything inside. There is usually a lot of dust in there, so now it’s time to use the compressed air. Wear safety glasses, and cover your mouth and nose. If possible, you can take the unit to the garage to prevent the dust from getting in the house.
Start with the fans. Get the can as close to the fan as you can with out touching it and give it several quick sprays. Do this with all fans (usually three) from the outside, spray the drives and slots. Spray all connectors. Give the power supply a few quick sprays. After all of these things are clean, you need to give the entire unit a good spraying. Begin at the top, and work down until there is no dust left in the computer. I like to go over the unit twice to make sure I didn’t miss anything. Put the cover back on, wipe down the case, and reconnect the cables.