Here are a few photos of dust inside computers and on components. Dust is removed when you bring a computer to me for servicing. As dust builds up inside a computer it limits the flow of air. This causes a build up of heat which will eventually cook either the processor, the graphics processor or the motherboard.
Dust on heat sink
Dust on processor heat sink
The fan sits on the heat sink which sits on the processor
Inside case before a cleaning. Notice dust under the power supply at the top and in the fans
