Some free PC diagnostic software downloads include Advanced SystemCare Free, Wise Registry Cleaner, Mz Ram Booster, Free Window Registry Repair and Toolwiz Care. The top download available at CNET.com as of 2015 is Advanced SystemCare Free, with over 100 million downloads.
Advanced SystemCare Free has a four-star Editors' Rating from CNET as well as the highest number of downloads among free diagnostic downloads. The software claims to clean PC systems and optimize performance. An upgrade is also available for purchase. It monitors malware and virus status and troubleshoots speed issues.
The Wise Registry Cleaner finds and cleans up redundant and bad information in the Windows registry. It deep-cleans the registry to find invalid entries and junk strings that slow down computers. It claims to be fast, easy and safe, while enabling beginners to clean a computer's registry. The company also offers an upgraded paid version. This software has a CNET Editors' Rating of four out of five stars and over nine million downloads in 2015.
Free Window Registry Repair has over two million downloads and a CNET Editors' Rating of three and a half stars. It has fewer features than the Wise Cleaner, but provides basic registry cleaning that helps speed up a computer.