CCleaner

CCleaner remains the most recognized name in system maintenance. It offers a comprehensive suite of tools including a junk file cleaner, registry optimizer, startup manager, and software uninstaller. Its 'Health Check' feature simplifies the process for beginners by scanning for privacy, space, and speed issues in one click. While it has faced controversy in the past, current versions are stable and highly effective for general users.

It is best for those who want a reliable, all-in-one solution that covers every aspect of basic PC maintenance.