Get Windows Vista Service Pack 1 RC (Update for existing Windows Vista users)
There are 3 different ways to access the Windows Vista SP1 RC depending on the unique business needs of individual users and their organizations.
- Windows Update Experience
The recommended method for installing Windows Vista SP1 RC on an individual computer.
- Windows Vista SP1 stand-alone packages
These packages support SP1 RC installations on all versions of Windows Vista with one, five, or a combination of the 36 Windows Vista languages installed.
- TechNet Subscribers: Get Windows Vista SP1 Release Candidate
Windows Vista SP1 Release Candidate is now available to TechNet Subscribers on Technet Subscriber downloads.
Be sure to read all the details at http://technet.microsoft.com/en-us/windowsvista/bb738089.aspx before you do anything. And please make a backup before you start the install process.