First, we are not supposed to issue hasty judgments regarding others and their earnings. A Muslim should think good of his Muslim brothers and sisters unless there is a clear proof to the contrary. Thus, if we know for sure that someone has bought the computer with haram money, then we should avoid using it. However, if the person has a mixed income of halal and haram money and can reasonably assume that the computer is not purchased with the haram money, then we can use it.
Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states the following: “If we know for a certain fact that the owner has bought the computer with haram or unlawful money, then we should not use it.
If, however, we are not sure of this fact, then we are not supposed to rush to make such a judgment, for as Muslims we should think good of our brothers and sisters unless we have clear proof to the contrary.