What registry cleansers actually 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 pinpointing 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 press the ‘fix ‘button the program will start and repair all the errors in your registry. Another thing you should 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 advisable to learn what other users say about it, either through user reviews of registry cleaners, or reports.