Microsoft says that Windows 7, the badly needed replacement for Windows Vista, the operating system so laughably bad it tried renaming it, is coming out in 2010. Officially. But Mary Jo Foley, the longtime Microsoft observer, thinks it's coming sooner — before the middle of next year, quite possibly. Foley has plenty of sources she talks to on the phone, but she does some of her best work piecing things together at her keyboard.First clue: Microsoft has said Windows 7 will ship before the next WinHEC event, a conference for PC makers who license Windows. Second clue: While Microsoft hasn't publicly announced a date for the next WinHEC, a New Orleans convention site lists it as happening next May — something Foley found not by dialing for dollops of information, but rather by Googling it.