I have tried another registry cleaning tool, called "Free Registry Cleaner" (v. 2.8).
This tool found more than 300 so called "registry problems" (before the registry scan, I have cleaned my registery with the CCleaner !).
After cleaning, my systems runs without any problem.
I am very astonished abount this huge amound of errors NOT found by the CCleaner.
Please use better topic descriptions in the future!
The reason CCleaner doesn't find as much is because it isn't as aggressive, however all registry cleaners have to be used with the notion that they can, may, or break something!
Using aggressive registry cleaners that list hundreds of items to remove will more than likely contain allot of false positives, i.e.; stuff you really shouldn't be removing or messing with as it can cause the re-installation of software, or worse Windows itself -- and the damage may not be obvious right away since it can literally take months to realize you have serious problem.
Ok, I have to apologize, my topic descriptions is bad.
Perhaps you are right, aggressive registry cleaner may cause problems in the future.