RegSeeker is best for advanced users, who are able to use an advanced tool to enumerate parts of the Registry so they do not have to search around.
But, in the hands of a simple user, it is a completely outdated "Registry Cleaner" that works powerful. It should not be used, unless they make it updated and safer. Not likely since they are not very popular of software makers. Not only that, they have not developed a product for over a year and a half, at least.