There are a lot of registry cleaners out there, none of them are someghing to brag about. The one thing i liked about ccleaner for a while is that it was very conservative in what it cleaned untill one day it broke my adobe photoshop installation, than it broke my autocad installation. after that i carefuly picked what i wanted deleted from the registry. To make this feature idiot proof and safe you need to carefuly make an exclusion list for keys that should not be deleted. I’ve had horror stories from a few friends that messed up their windows so bad with registry cleaning from ccleaner as well so i know what i’m talking about.