Well, the clean up will clean all registry keys that are invalid, as shortcuts, and other stuff, it doesnt matter if it is a clean install or not, windows has errors in the registry and they are not fixed by magic, i suggest you to do the power clean, maybe some file is corrupt or something is wrong in the windows registry or in some dll, and this will fix it. Im trying to help you, so you could try it, you dont have anything to lose. In every machine i have checked, there is always some errors in windows, and the comodo system cleaner helps to make windows to run better and to fix the errors.