For free try Auslogics Registry cleaner, you can down load it from cnet.com in their downloads section. For a paid version I hear a lot of good things about RegCure. I took an A+ Cert prep course at my local college and both my instructors recommend RegCure. I'm one of those types of people that "why pay for something when I can get it for free". The choice is ultimately up to you. Also to keep you system in tip top shap I recommend these software applications as well: Adaware AE, Spybot s&d, Malwarebytes, spywaredoctor from google pack, Advance System Care 3, Auslogics disk and registry cleaners, AVG for antivirus, Windows defender. Again all these are free and can be downloaded from cnet.com.