12.6 Windows 9x/2000 Registry Problems
12.6.4 Cleaning the Registry
An important part of maintaining a healthy computer is cleaning the registry. As the system is used and applications are installed and uninstalled, values are left behind in the registry. They remain even if they are uninstalled with the "Add/Remove programs" wizard. If the Registry becomes too cluttered with old files and old application registry entrees, it can cause problems and degrade system performance.

Third Party Registry Cleaning Tools
Third party registry cleaning tools are recommended to edit the Registry. Popular third party registry cleaning tools are the Norton WINDOCTOR and Microsoft RegCleaner.