It's Windows reimagined and reinvented from a solid core of Windows 7 speed and reliability. It's an all-new touch interface. It's a new Windows for new devices. And it's easy to try now-whether you're installing it for the first time, or moving from Windows 8 Consumer Preview.
Running Windows 7, Windows XP or Windows Vista? Then this is the upgrade to Windows 8
Customize your Start screen with Live Tiles
Once you install Windows 8, Windows 8.1 is available as a free update directly from Microsoft