If you have to use a registry cleaner and I don’t care which one, the first step should be a back-up of your registry.
As faR AS Norton Utilities goes, it’s not the most compleat reg. cleaner but, it at least doesn’t delete reg. keys needed by the operating system.
And as softwareguy says, some of the reg. tweaks can take a long time before they show up. Usually by then, it’s to late to fix anything.