Hi .. I been using xp pro when it first came out in 2002 and all I ever do is clear out all my temp files / cookies , defragment the drive , use disk cleanup , ad aware / spybot search N destroy , cwshedder , mru blaster , spyware blaster , nod32 anti virus , sygate firewall , Hosts file program ... With all these programs running I never found the need to use a registry cleaner and my computer is running really smooth , Though I have heard other using registry cleaner and later on having problems with there computer , Now whether this has anything to do with them using a registry cleaner , I don't know but , it has made me wonder