Which materials should a computer never be placed on?

There are a lot of people who just place their personal computers in random places when this should not be the case. Personal computers should be placed in areas that are well-ventilated. The air has to circulate properly so that the personal computer will not become too hot.

Based on the choices that are available, a computer should never be placed on the following: Carpet because it might cause the personal computer to become too hot. It may come to a point that it will ignite and cause a fire. It should never be placed on plastic as well as there is a possibility that the plastic will melt once again because of the personal computer’s heat.