is registry cleaner safe ?

here is the download link http://www.softpedia.com/reviews/windows/Eusing-Free-Registry-Cleaner-Review-53815.shtml

i just want to make sure its safe and free to use before downloading

my dell is running really slow so I’m looking for a free registry cleaner download .I know that sometimes you and pick up a virus by choosing a wrong download .

are they safe to use?
i use eusing free registry cleaner and so far no problems that i have noticed anyway.

i have also the reg cleaner hat comes with ccleaner and again, so far no problems
but i have heard some say they are not safe while others say they are.

What does it do?
Will it remove any important files that I have?

I keep on getting a pop up saying that I need to clean my registry, so I mind as well do it.

Anyone recommend a free registry cleaner?

what is the best free registry cleaner to use