While the public continues to enjoy the Windows 8 Release Preview, Microsoft is reported have already completed the development cycle of their upcoming version of Windows.Meanwhile an Enterprise version of Windows 8 has reported to have leaked across various file sharing sites.
The leaked version is reported to be the N variant which is generally available in the European Market. The N edition of Windows does not include a bundled copy of Windows Media Player per the ruling of Ruling of the European Commission in 2004.
We do not recommend searching for or installing the leaked version of Windows 8 as you may as well enjoy the Release Preview until Microsoft publicly releases the final version on October 26th.
MSDN and TechNet subscribers are reported to receive an early copy of Windows 8 on August 15th.
source - TheVerge