What registry cleansers usually do is they scan your registry for all junk that has accumulated over a considerable period of time. Once they do that they will present you with a report describing what the problem is with your registry. This will most often be a detailed report which you can go over and decide to fix. Once you click the ‘fix ‘button the software will launch and repair all the entries in your registry. Another thing you need to know about registry cleaners is that before you do anything make sure you backup your registry. Before you select your registry cleaner software, it would be a good idea to find out what other users say about it, either through user reviews of registry cleaners, or reports.