I googled thusly:
First hit http://support.microsoft.com/kb/971767 explains:
Windows 7 RC
Windows 7 RC expiration
June 1, 2010, Windows 7 RC will expire.
To continue using your computer, you should prepare to install the retail release version of Windows 7 or install an earlier version of Windows before the June 1, 2010 expiration date. You will be unable to upgrade from Windows 7 RC to the retail release version of Windows 7. However, you can back up or transfer your data to your next or previous operating system.
Windows 7 RC expiration functionality
Effective February 15, 2010, the expiration notification process begins:
· Windows 7 RC users receive an expiration notification in the task bar one time per day.
· Windows 7 RC users are presented with the Notification Wizard one time every four hours and then one time every hour.
Effective March 1, 2010, Windows 7 RC enters the next phase of expiration:
· Expiration notifications in the task bar continue.
Computers that are running Windows 7 RC restart every two hours.
Important When the computer restarts, your work will not be saved.
Effective June 1, 2010, Windows 7 RC expires:
· Windows starts to a black desktop.
· Windows 7 RC users are presented with a Windows Activation screen. The screen states that the Windows that you are running is not genuine.
· Computers that are running Windows 7 RC restart every two hours.
So the short answer is back-up and reinstall. Might be a good time to investigate the Windows Easy Transfer facility:
Also, a Windows Team blog post regarding RC expiration (which refers to the KB article above):
> -----Original Message-----
> From: Technology Discussion at UVM [mailto:[log in to unmask]] On
> Behalf Of Larry Kost
> Sent: Tuesday, February 16, 2010 9:31 AM
> To: [log in to unmask]
> Subject: Windows 7
> I have a Faculty member who installed the pre-release version of
> Windows 7
> and it is now saying that it will stop working in 13 days. Is it
> to upgrade to 7 Enterprise, or will it require a clean install?