Quote from gnome:
You might want to check the bottom part of the processes page.. below the slider. For what you've shown, nothing is hogging the CPU. Unfortunately, that means the troublemaker is not obvious and you'll likely have to find it by trial and error. And the problem could be due to something CCleaner "cleaned" but should not have. If you get to the point of reinstalling your OS and software, evaluate performance having not used CCleaner... that is, CCleaner should the the last thing you do.... any perhaps not use it at all.
Agreed.
You may have accidentally deleted an important "DLL" file that the operating system uses and now your registry is not as it was.