Use Vista? Installed SP1? Why not clean up all the old files and get some extra hard drive space back?
I saw this article today talking about the necessity of doing just that: http://www.labnol.org/software/tutorials/finish-install-windows-vista-sp1-clean-junk-files/2641/
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.
Naturally, these files occupy important disk space. If you are satisfied with the performance of Windows Vista SP1 and 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.