“…Windows Vista SP1 File Removal tool (Vsp1cln.exe)…you can run after you install SP1. This tool removes older versions of components that have been updated in SP1…you should run Vsp1cln.exe if you want to reclaim this disk space after applying SP1 and if you will not need to uninstall SP1…you cannot uninstall SP1 after you run this tool…%windir%\system32\vsp1cln.exe”