When you start a Windows 8 machine, you’re greeted with a screen that shows the time and a pretty picture. To get past it with a touch-screen device, swipe upwards with your finger from the bottom edge of the screen. If you have a keyboard, hit any key. Next, you’ll see a mosaic of Live Tiles, each representing an application. Programs specifically written for Windows 8 will run in this new environment, which is unofficially nicknamed Metro.