Earlier this month we discovered that the VPC (Virtual PC) images we distributed as part of the VS 2008 Beta2 release this summer unfortunately have an operating system timeout of November 1st of this year. The standalone VS 2008 setup packages do not have this issue - only the pre-built VPC images do. So if you've installed VS 2008 on your own operating system image you won't have any issues.
If you are using the Beta2 VPC images, though, is is really important that you retrieve all of the data that you have saved in them before November 1st (after this the OS won't work).
Today we re-released the VS 2008 Beta2 VPC image downloads (without the timeout setting) that you can download and move to using instead here.
Sorry for the mix-up,