I am looking for a good free registry cleaner, but it is a bit hard to tell what really may be a good one, looking for help
CCleaner http://www.piriform.com/ccleaner/features is popular, free, and pretty benign.
I'm going to make a couple of suggestions before using any registry cleaner.If you have a backup software like Acronis or Ghost make a current BU.At least use a registry backup software like ERUNT. You may need a linux type bootable disc to use ERUNT if the registry cleaning won't let you boot into your OS. TRK is the one I use. CCleaner will also let you make a backup of what it removes . I suggest doing that also.You can also let it just remove one registry entry at a time slower but safer. Just don't get in a hurry .
Glary Utilities also is excellent.
What OS are you using?