John, I use Advanced windows care from
http://www.savemybutt.com
Their is also a registry cleaner in ccleaner, which is also available from
the download section of the same page.
Their is also a registry defrag program, which works well on windows XP, but
not on windows 7.
Mike from savemybutt, doesn't like the upgrade to advanced windows care,
called advanced system care.
I agree, because you can't tell what it is doing.