regclean is not meant to be used on winxp. i would be hesitant to use it. i also have norton utilities. windoctor is not a registry cleaner. it looks for specific errors in the registry. regvac can be used on xp and does a better job than regclean. the registry cleaner in system mechanic is not a cpmplete registry cleaner, as you will notice by how fast it runs. it looks for specific things. try nbg clean registry. you dont have to delete registry entries, but you will see just how much junk is in your registry.