Windows Vista Service Pack1 RC Refresh (Build 17128) has been made available to public/testers for testing recently, It's available through Windows Update. If you want to try it , please check it here; Windows Vista Service Pack 1 RC Refresh Public Availability Program. (Build 17128)
But there are some points, one should note :
-SP1 RC Refresh is an optional update – if you are already running RC (17052) , you do not need to install this build.
-Windows Vista SP1 RC Refresh fixes issues that were preventing successful installation of the service pack. Install the RC Refresh if you are having problems with RC.
-If you are already running SP1 RC or any previous version of SP1, you need to uninstall it prior to installing SP1 RC Refresh
-If you install Windows Vista and then install this release candidate of SP1 without first activating Windows Vista, you might not be able to uninstall the service pack. Either activate Windows Vista before you install SP1 or activate SP1 before you attempt to uninstall the service pack.
-To uninstall previous version of Windows Vista SP1
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.
Your system will now uninstall the previous version of Windows Vista SP1 Beta and may reboot multiple times.
Please wait one hour after uninstalling a previous version of Windows Vista SP1 before installing Windows Vista SP1 RC Refresh. 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 Refresh is time-limited software.Windows Vista SP1 RC Refresh 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.
Microsoft does not recommend installing this software on primary or mission critical systems.
For more details ,Please check