Windows 7 Beta expiration date was on 1 August, 2009, to continue using your computer you should prepare to install a later pre-release version of Windows 7. This installation is necessary to install the retail release version of Windows 7, to back up your data and reinstall an earlier version of Windows before the August 1, 2009 expiration date. You cannot upgrade from Windows 7 Beta to a later prerelease of Windows 7 or to the retail release version of Windows 7, but you can back up or transfer your data to your next or previous operating system.

The expiration notification process begins June 17, 2009. Windows 7 Beta users will receive an expiration notification in the task bar once in a day. Later, Windows 7 Beta users will get the Notification Wizard one time every four hours and then one time every hour.
From July 1, 2009, Windows 7 Beta will enter the next phase of expiration. Expiration notifications in the task bar will continue to appear and Computers that are running Windows 7 Beta will restart every two hours.

Windows 7 Beta expires will expire on August 1, 2009. Windows will start to a black desktop; Windows 7 Beta users will get the Windows Activation Expired dialog box during logon and then again in every one hour. Computers that are running Windows 7 Beta will restart in every two hours.

Expiration Dates and functionality of Windows 7 RC:

Windows 7 RC expiration date is February 15, 2010. Windows 7 RC users will receive an expiration notification in the task bar one time per day. Windows 7 RC users will get the Notification Wizard one time every four hours and then one time every hour.

Effective March 1, 2010, Windows 7 RC will enter the next phase of expiration. Expiration notifications in the task bar will continue. Computers that are running Windows 7 RC will restart every two hours.
Windows 7 RC expire effective June 1, 2010. Windows starts to a black desktop. Windows 7 RC users will get the Windows Activation screen. This screen will state that the Windows that you are running is not genuine. Computers running on Windows 7 RC will restart every two hours.

Please note that When the computer restarts because of the reasons mentioned above, your work will not be saved.

About Windows 7 RC

Windows 7 RC (Release Candidate – a final test version) is designed specifically for IT Professionals, so that they can test their software and hardware on a final version of the product. This not the final tested version, there are some risks involved in using it. According to Microsoft, people who wish to use this version should have some specific skills. They should know how to: Troubleshoot problems, Burn an ISO image to create a DVD, Install Windows, Back up and restore their PC, Set up a network, and Create and use a system recovery disk.Since Windows 7 RC is a work in progress, users may encounter technical difficulties. Hence, the users should not install the RC on their primary production machine. Some serious issues with Windows 7 RC are :• Some software applications, including antivirus programs, might not install or work correctly• Printers and video cards, may not work• Access to corporate or home networks may go down• Users’ files may get corrupt