When windows 8 Release Preview will expire? How long I can run it? Must I buy the final version of windows 8 when its released?

The Win 8 RP will deactivate in early January next year was the last I read. This means that if you wish to continue using Win 8 after the final version is released, then you will have to buy it because shortly after it is officially released, the final beta will deactivate and you will be left with nothing.

Or just go back to the version of Windows that came on your computer and forget about Windows 8.
It's not your FREE OS! It's released for testing purposes only!

:cool: