The registry is one of the most important aspects of your PC; in fact, your PC would fail to work correctly and efficiently without it. Think of it as the card catalog system of your local library. The card catalog exists in the library for the sole purpose of letting a person know exactly where a book in the library is located. It tells the author's name, the publication year, and the title so a person will know if the book they are looking for is the correct one. The registry of a PC works in the exact same way, except the PC is the person looking through the card catalog. Information about many aspects of the PC is stored in the registry, such as the user profiles and preferences of individuals who use the PC, settings for installed software and hardware, information about recent updates, and so on. Therefore, it would only seem natural that the registry eventually needs to be cleaned, much in the same way a card catalog needs to be reorganized.
For the individuals who do not wish to browse the registry and edit certain items out of the registry there is CCleaner. This little program should come standard on every PC, as it is like having a janitor inside your computer. It deletes all the gunk that builds up in your PC over time (cookies, temporary internet files, history, and so on). In addition, CCleaner also has an option to clean your registry. It scans the registry in search of broken and useless registry files and rids them, making the registry clean again.