Windows 8 is an upcoming version of Microsoft Windows, a series of operating systems produced by Microsoft for use on personal computers, including home and business desktops, laptops, Microsoft Tablet PCs, and Home theater PCs. According to unofficial sources, the release date for Windows 8 has been set for October 2012, three years after the release of its predecessor, Windows 7. Windows 8's server counterpart, Windows Server 2012, is in development concurrently with Windows 8. The most recent official pre-release version of Windows 8 is the Release Preview, which was released on May 31, 2012.
Unlike Windows 7, which was intended to be a more focused, incremental upgrade to the Windows line, Windows 8 has been "reimagined from the chipset to the user experience" to connect more with the user. It features the Metro interface that is designed for touch screen input similar to that in Windows Phone and on the Xbox 360. A version of Windows 8, called Windows RT, also adds support for the ARM processor architecture in addition to the previously supported microprocessors from Intel and AMD.
if you want to download you can click here:http://windows.microsoft.com/en-US/windows-8/release-preview
Note before you download: Windows 8 Release Preview is prerelease software that may be substantially modified before it’s commercially released. Microsoft makes no warranties, express or implied, with respect to the information provided here. Some product features and functionality may require additional hardware or software.
Important: If you decide to go back to your previous operating system, you'll need to reinstall it from the recovery or installation media that came with your PC, which is typically DVD media. If you don’t have recovery media, you might be able to create it from a recovery partition on your PC using software provided by your PC manufacturer. Check the support section of your PC manufacturer’s website for more information. After you install Windows 8, you won’t be able to use the recovery partition on your PC to go back to your previous version of Windows.