Whenever a program is installed on a computer, numerous keys are created in the registry of the operating system. These keys (small entries like file folders that help run a program) accumulate over time and can cause a lag in the computer's speed. Registry cleaners analyze the registry and identify keys that should be deleted. A variety of free registry cleaners are available on the Internet.
Previously know as Crap Cleaner, this is a very light and popular registry cleaner. It cleans up registry files without damaging the computer. Unlike some registry cleaners, it is safe to run this software as it does not locate deep-rooted keys in the registry.
Comodo Registry Cleaner
Comodo registry cleaner is powerful software that goes deep into the registry to locate worn-out registry keys. It is always a good idea to back up the registry when using this software (the software provides an option to back up the registry).
Eusing is a powerful registry cleaning tool that can find numerous useless keys in the operating system. It has an easy-to-use interface.
Argente is a registry cleaner that has earned praise and criticism. Some users have found it really helpful, and some have complained that it messed up the operating system. It digs up registry keys from deep within the system and helps the user maintain a clean registry.
EasyCleaner is similar to Ccleaner but has one advantage--it has an up-to-date text file that contains a list of all updated registry keys. This enables the user to avoid missing any single registry key that should be deleted.