 When millions of computers throughout the world that were running Microsoft Windows all of a sudden stopped working Friday, it opened our eyes to just how pervasive computers are. Sally Walker is the former cyber chief of Britain's Government Communications Headquarters, an intelligence agency. It does emphasize that we live in a world of dependency and vulnerability and that disruption can and will happen. And IT is at the core of our day-to-day operations, our businesses, our economies, our communities.