What does the Windows registry contain information about?
The Windows registry is a database, which contains information about everything on a computer – hardware, the operating system itself, other system software, application-level software, users and user groups, user preferences, etc. Every time a change is made in any of the above categories, this is written to the registry. Sometimes, especially when the uninstallation script of an application has not been written properly, it can happen that the application has been uninstalled but the respective entries in the Windows registry haven’t been deleted. While this generally will not crash the registry, such information shouldn’t be there and that it is why the registry must be cleaned periodically.
