RegClean Pro is software known as a Potentially Unwanted Program (PUP). At first sight it is nowhere near a virus or malware in general. The main problem with this software and their distributors is that the software is forced installed on users computer using bundled customs installation software. When you download freeware from the internet, it is often bundled with custom installation software. Using this method advertisers monetize their free software.
RegClean Pro from Systweak is software that is generally offered in lots of customs bundled installation software. This software is also known to find and report problems in your computer that can be fixed with free software. There is absolutely no need in buying a license from this software to solve the problems or alerts found using RegClean Pro.