Upgrading From Windows 7 RC To Final Version Without A New Installation

I’m sure you noticed that Windows 7 RC started displaying warnings and notifications to back-up your data and install a new, clean installation of Windows 7 RTM (Final version), or other operating system.

Windows 7 RC will stop functioning on June, 1st. That does not mean that you can use it properly to that date, because Microsoft will start shutting down your computer every two hours, starting from March.

From: http://ping.fm/50dfb