The 20-year death grip that Microsoft has held on the core of computing is finally weakening -- pried loose with just two fingers. With one finger you press "Control" and with the other you press "right arrow." Instantly you switch from a Macintosh operating system to a Microsoft Windows OS. Then, with another two-finger press, you switch back again. So as you edit family pictures, you might use Mac's iPhoto. When you want to access your corporate e-mail, you can switch back instantly to Microsoft Exchange.