BAD, BAD advice!!!!!!
Never use a Registry Cleaner.
If you have to do it, do it manually; or leave it alone!!!!!
I agree.
The problem is that 99.998% of windows users don't know enough of what the
registry is and how everything works to do it manually. I personally know
programmers that I wouldn't let loose (with regedit) on my own machine. In
fact, some of them belong to the most dangerous ones: they *think* they
know it all.
And knowledge of the registry isn't enough, sometimes you also need
knowledge of the internal workings of an application.
So instead of doing it manually, people resort to tools that are introduced
to them as white magic coming from the Gods of the Holy Smoke Within.
In reality, what makes some of those gods gods is that they are lacking
less knowledge of how a PC works than mere mortals.
But with all that being told, keep in mind that most of the time, these
tools will just do their job as the maker expected. And the times they
don't, or when they fix one thing and break two others, let's just say that
anyone who doesn't have a recent backup (of a known good state, preferably)
deserves all he gets.
So
1) make backup
2) run registry cleaner
3) if works, be happy. if not, restore.
