Once upon a time, Microsoft dominated the tech industry; indeed, it was the wealthiest corporation in the world. But since 2000, as Apple, Google, and Facebook whizzed by, it has fallen flat in every arena it entered: e-books, music, search, social networking, etc., etc. Talking to former and current Microsoft executives, Kurt Eichenwald finds the fingers pointing at C.E.O. Steve Ballmer, Bill Gat