Registry cleaner is a third party vendors advertising to clean windows operating system to increase functionality of a computer. However, it is also a very controversial topic. Those against it claimed that these systems are associate with malware. Those for it said it cleans up redundant, invalid, and useless database entries in the registry. Whether you are for or against it, check Iolo registry cleaner if you must try it. It can't hurt. Don't we all want improved system?