Selters

Hi I have used CCleaner for a long time and is very pleased with it. I cleaned registry today, and after that I ran a program called RegSeeker.exe (was in a forum where it was recomended to use) and that program found 1165 errors still in the registry. Can anyone tell me why it is so huge difference between CCleaner and RegSeeker (I have used other programs aswell and get the same result (RegCure, SpeedUpMyPc, .....))?