With the release of Windows Server 2008 and Windows Vista SP1 Microsoft removed the old management tools that shipped with RTM Vista.  When you install Windows Vista SP1 you will notice that the Group Policy Management Client (GPMC.msc) and other features are no longer available.  They have been uninstalled from your system.

Microsoft replaced the old uitilities with updated version in the Remote Server Administrative Tools  (RSAT) package.

Download the 32-bit version for Vista SP1

Download the 64-bit version for Vista SP1

Once you have downloaded and installed the administrative tools you need to turn the features on.

1. Open Control Panel and go to Programs and Features.
2. Click Turn Windows features on or off located on the side menu.
3. Check Remote Server Administrative Tools and hit OK.