Just a couple days left before Windows 7 beta builds will expire.
Update: Windows 8 Is Out Guys
Windows 8 is out now and no beta is currently going on
Upgrade to 8.1 today!
Many people still use a beta build and need more time to update to RC.
Windows 7 PlusPatch (1.0.2 currently) is a little tool that you can use to disable the expiration completely. It works on all Windows 7 builds.
This is only a temporary solution and you should upgrade to RC as soon as possible!