Install Windows Vista SP1 Release Candidate through Windows Update
Windows Vista Service Pack 1 (SP1) Release Candidate (RC) is available through Windows Update. Please read the following instructions before you install.

Before You Install

• You must uninstall any previous versions of Windows Vista SP1 before installing Windows Vista SP1 RC

To uninstall previous version of Windows Vista SP1
1. Open the Programs and Features control panel and select View installed updates. In the Microsoft Windows section, right-click Service Pack for Windows (936330) and select Uninstall.
2. Your system will now uninstall the previous version of Windows Vista SP1 Beta and may reboot multiple times.
3. Please wait one hour after uninstalling a previous version of Windows Vista SP1 before installing Windows Vista SP1 RC. The installer service needs to clean up and complete the uninstall prior to installing the RC. Failing to do this can result in installation errors when installing the RC version.
• Windows Vista SP1 RC is pre-release software and will change before the final release. Windows Vista SP1 RC is for individuals, organizations, and technical enthusiasts who are comfortable evaluating pre-release software and is provided for testing purposes only. Microsoft does not recommend installing this software on primary or mission critical systems. Microsoft recommends that you have a backup of your data prior to installing any pre-release software.
• Windows Vista SP1 RC is time-limited software.
  Windows Vista SP1 RC will no longer operate after June 30, 2008 and should be uninstalled prior to that date. After installation your desktop will show the text “Evaluation Copy”. This does not mean that your system is no longer genuine but that you have installed a test version of software which is time-limited. The “Evaluation Copy” text will appear on your desktop after the second reboot after installing the service pack. Likewise, the “Evaluation Copy” text will remain on your desktop during the first reboot after uninstall the service pack, but will disappear after the next reboot.
• If you install Windows Vista SP1 RC it is strongly recommended that you install the final version of Windows Vista SP1 when it is released. To do this, you will be required to uninstall this RC version of Windows Vista SP1.
• Assisted support (phone, email and online chat) is not available from Microsoft Help and Support for this RC release of Windows Vista SP1. Self-help and peer support is available through the Windows Vista SP1 forum.
• You must have a genuine copy of Windows Vista installed prior to installing Windows Vista SP1 RC.