The Windows registry is a database on Windows PCs that contains configuration settings for low level operating system software as well as added software applications, such as favorite games or photo processing software. The system kernel, user interface, device drivers, and third party software applications are all contained in the Windows registry.
Over time the registry can accumulate incorrect entries or entries that relate to software that has been removed from the PC. A registry full of incorrect or unneeded entries can lose efficiency. Registry cleaner software is designed to remove these unnecessary entries in the registry, allowing the registry to run at its optimal efficiency.