An effective insight about ICT environmental sustainability requires to pay attention also to the software features, being this another responsible for the CO2 emissions. The energy consumption in the computer's use phase doesn’t depend only from hardware but also from software configuration and from its efficiency. Software is also responsible for the Induced hardware obsolescence. The actual computer lifecycle is shorter than the potential one. Some real data and interview will give evidence on how software improvements, aimed to make more effective the Information system configuration, will lead to energy consumption reduction. A software based approach will also allow a longer use for PCs, respecting the environment, saving energy, emissions and money, and, in the meantime moving toward the cloud computing paradigm.