Users still running Windows 7 Beta will see their systems spontaneously shutting down starting today. If you wish to continue your Windows 7 experience, you'll need to install the free release candidate otherwise you are encouraged to downgrade to Vista/XP. Microsoft is also recommending that users moving from Windows 7 Beta to the RC preform a clean install.
Windows 7 RC will be available for download through July, and will begin a similar bi-hourly shutdown process starting March 1, 2010. The OS is scheduled for general availability release on October 22, 2009.