1. Turn off the PC, remove all cables and open the case cover.
2. Don’t use a vacuum cleaner as it will build up static electricity and you shouldn’t use those specially treated dust rags to clean your computer, unless you are sure, that they don’t use static electricity to catch dust.
3. The only good way to remove dust is by using compressed air cans, which are usually available in electronics supplies stores. Blowing away dust clumps can be messy- especially if you never do it before, so it would be better to do this outdoors.
4. A compressed air can usually uses a thin straw. It will allow you to quickly direct the air at a consistent speed.
5. If you see plenty of dust floating around your computer as you are blowing them off, remove the straw and blow a couple of short bursts around the case, so you can prevent it from settling in again.
6. While you’re removing dust, check all fans inside your computer, including the processor fan and power supply fan. If too much dust accumulates on the leading edges, the airflow can be disrupted, which means the fans may not be able to cool your computer effectively.
7. As the last step in eliminating dust, blow the compressed air from the inside of the computer through the vents. However, it won’t be possible to clean the power supply this way. The only way to do it, is by opening the power supply, which may not be a good idea unless you are skillful enough. Instead, you should just gently wipe the power supply’s vents and make sure that you don’t force the dust into the power supply.
The best way to clean you computer is to completely disassemble the computer, by removing the processors, heat sink, graphic card, memory modules, cables, hard drive, optical drive and all adapters. You may need to ask an expert to do this, some technicians may even wash the motherboard with detergents. Don’t forget to apply a fresh layer of thermal paste on the CPU heatsink when re-assembling the computer.
To make it easier to clean your computer in the future, you can cover the vents with filters. Get air conditioner filters, in the hardware store, and cut it to match the vent shapes. It may not be possible to filter all vents, however they will help in cleaning your computer, as the dust will be trapped in the filters, before it reaches the computer components. If the filters are very dusty, replace them. If you delay, the dust may disrupt the air flow and overheat your computer.
In dusty places, you may need to clean your computer’s interiors every few months, especially if smoking is allowed in your room. Under most situations, you should clean it each year.