(Infoworld) A United Nations University study into the environmental impact of personal computers, due to be published later Monday, has found that around 1.8 tons of raw material are required to manufacture the average desktop PC and monitor and that extending a machine's operational life through re-use holds a much greater potential for energy saving that recycling. According to the study, the manufacturing of one desktop computer and 17-inch CRT (cathode ray tube) monitor requires at least 240 kilograms of fossil fuels, 22 kilograms of chemicals and 1,500 kilograms of water. In terms of weight, the total amount of materials used is about equal to that of a mid-size car.