Excerpt - REDMOND, Wash. -- Jim Allchin, a senior Microsoft Corp. executive, walked into Bill Gates's office here one day in July last year to deliver a bombshell about the next generation of Microsoft Windows. "It's not going to work," Mr. Allchin says he told the Microsoft chairman. The new version, code-named Longhorn, was so complex its writers would never be able to make it run properly. The news got even worse: Longhorn was irredeemable because Microsoft engineers were building it just as they had always built software. Throughout its history, Microsoft had let thousands of programmers each produce their...