Our recommendation is to only use ccleaner (free download), but stay away from it's registry cleaning options. The default settings are useful.
Kees
I've read on numerous site that they do more harm than good. That some cleaner's will remove file's/folder's which are not in use but you may need at a later stage. And tweaker's are much the same......Can you please advise Me and other's as to what is safe for us novice's thank you....

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic