Registry Tuning refers to the process of optimizing the Windows Registry, a database that stores configuration settings and options for the operating system and installed applications. By adjusting specific entries, users can improve system performance, enhance security, and resolve issues. This tuning can involve cleaning up unused entries, modifying values for better efficiency, or adding new keys to enable features. However, it is essential to proceed with caution, as incorrect changes can lead to system instability or crashes. Always back up the Registry before making any modifications to ensure a safe recovery if needed.