The term "green" has become synonomous with helping improve the environment, and has become a marketing buzzword. Whenever the term is used, it's clearly meant to imply that the product or service being touted is environmentally friendly in some way. Clearly, the marketing folks at Microsoft know that, and are trying to draw attention to OneCare by using the term "green" in its central OneCare slogan.
OneCare has nothing to do with helping the environment. The green slogan plays on the fact that when OneCare finds a computer to be in good health, its icon turns green. But Microsoft knows -- or certainly should know -- that when people read the slogan, they'll think that OneCare is in some way environmentally friendly. So it's time to pull the plug on this misleading campaign.