Most of what has been said above about Windows registry is right.
Windows registry is the central data base that stored information for software, hardware, and Windows settings, etc. It is necessary to start Windows normally. With time, registry will get bigger and bigger and full of holes, errors, and invalid entries, which can lead to your computer pop up error message, slowdown and even crashes.
Some people say that registry cleaner does more harm than good, it's partly right. Novice users, and even professional need to be careful when using a registry cleaner & optimizer.
Then, is it necesary to use it? The answer is YES. Manual searching for registry errors and repairing it is an impossible task for most people, and a reliable registry cleaner can help them to do this job easily. And good results can be obtained if it is used properly.
Hope it helps!
