Registry cleaners really should never be used, period.
CCleaner is an excellent tool otherwise, but avoid the registry cleaner like all registry cleaners.
In the final analysis, as is so often the case, it is essential that you be taking full system image backups, and on a regular basis, of any machine whose loss would be catastrophic (and that generally includes one's own personal computer).
Brian Version 1703, Build 15063.296, Home 64-bit
Many are under the gross misapprehension that the Constitution is a cage and a laundry-list rather than a framework upon which great things have been and still will be built. Many things that are entirely Constitutional are not "in the Constitution," but are allowed under it.