I never did a registry clean. I will never do it. I don't belive it is necessary under normal circumstances; only if there is something specificaly wrong. And then you will use a specific program like an uninstaller or a malware removal software.
Most so called cleaners will only screw up things. And the reliable ones won't make a difference.
If you want to do a common sense test of where this snake oil programs stand in the overall software world just Google "registry cleaner" with WOT enabled and see the number of orange and red circles.
After running a cleanup and reg fix with CCleaner, a friend's older laptop became much faster.
Even if the speed of the computer was the same, CCleaner is an easy way to clean out junk. Just one scan removed about 1.5 GB of temp files from different apps.
With an older computer...1.5GB is a lot.
