Is CCleaner recommended?

There are some great reviews, but won't deleting registry files mess up your computer?

I use itIt removes unnecessary registry files, and it gives you the option to create a registry backup if anything does go wrong

it doesnt actually remove registry files, which will indeed mess up your computer. Think of the registry as a database, what programs like ccleaner do is they remove obselete or unused entries from the registry, making it faster for the computer to process the remaining entries. There is still an element of risk, but if you use the right programs and have some idea of what you are doing then it is minimal.