Microsoft Windows Vista SP1 RC Refresh
Windows Vista Service Pack 1 RC Refresh is available to Beta testers through Windows Update. Experience the WU installation path for Windows Vista SP1 by following these simple steps and give us your feedback to improve our quality.
There are two ways to install the service pack, first, as a pop-up notification that the service pack is ready to be installed (this is the method in which most users will install the service pack) and using multiple manual installations from Windows Update. The first method is the simplest, but may take up to four days for the Windows Update Automatic Update feature to deliver each of the 3 prerequisites and the service pack. Windows Vista SP1 distributed through Windows Update will be applicable to Windows Vista machines that are running on any of the 36 languages supported by Windows Vista RTM.
Download: Vista SP1 RC Refresh Public Availability Program 936330
Link: Homepage