Windows 8 Release Preview ISO files are provided if you are on a PC running Windows and want to install the release preview on another partition, another PC, or a virtual machine, we recommend you download Windows 8 Release Preview Setup.
Windows 8 Release Preview ISO files (.iso) are provided as an alternative to using Windows 8 Release Preview Setup. If you are on a PC running Windows and want to install the release preview on another partition, another PC, or a virtual machine, we recommend you download Windows 8 Release Preview Setup and use the built-in tools for converting an ISO image into installation media, such as a DVD or USB bootable flash drive.Download
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.