A curious question

Before cleaning the registry I created restore point but when reverting to earlier created restore point somehow the problems I ran into after cleaning didn’t disappear.

Even after reverting to a point where before I installed CSC, the CSC was still listed as being installed.
Could someone enlighten me as to why these happened? Why was the restore point useless to prevent damage to system registry. Why did my PC still list CSC as being installed even after I restored to a point before I installed CSC?