When you install Windows Vista Service Pack 1 on your computer, the SP1 installer will not remove the older versions of Vista files from the hard drive. This is because the older files may be required in case you decide to uninstall SP1 later from the system.
Related Guide: Recover Disk Space in Windows
Naturally, these files occupy important disk space. If you are satisfied with the performance of Windows Vista SP1 and are unlikely to remove it later, why not reclaim some disk space by removing all the older Vista files.
There are no manual steps involved. Just open your Windows command prompt and type vsp1cln.exe (short for Vista SP1 Cleaner). It takes less than a minute to execute.
*vsp1cln.exe is added to your Windows Vista System folder after you install Vista SP1.
This will make Windows Vista Service Pack 1 permanent on this computer. All the older files are deleted now and your hard disk has tons of extra space for other important files like videos and photos.
You computer need not be connected to the Internet for running the Vista SP1 cleaner tool. And you won’t be able to remove Windows Vista Service Pack 1 later.