RegClean/com has been registered since 2000 and is under MarkMonitor who monitors trademarks for people. It has no landing page. RegCleanPro/com is registered since 2004 and points nowhere right now.
There is a trademark for RegClean Pro dating to 2011 with this as the category :Computer software for cleaning and optimizing a computer and improving a computer's performance that may be downloaded from a global computer network.
RegCleanPro /net also registered since 2004. The person holding the dot com is likely the same person holding the net. It is sitting on a landing page with ads.
I am not sure why you are asking about this domain but with an existing trademark I see no other usage except for the trademark holder who doesn’t even currently have a developed site.
Avoid most trademark domains until you know more about this stuff. I see you have RegClean/ net. Take it off a page with ads and get rid of it.
Amend your post to mask the name as this will show up on Google.