"Registry "cleaner": There is no such thing. They mostly do nothing useful but sometimes they cause serious damage." ANSWER ~>
As far as "Damage", be very carefull if you attempt to EDIT the Registry yourself and, YES, inappropriate or Impropper Versions of Registry Cleaners for your Version of Windows, may function BUT Mess it up!
Seek out the Correct Version of a Registry Cleaner for your Specific Version of Windows (or what ever Operating System you are using) AND Be Sure it's Completely Compatible with your System 1st!
Like many Antivirus programs, they may require that you pay an Annual Fee to continue to recieve updates, after your Initial purchase which covers you for 1 year at the basic level.
IF By Chance, you use Symantec's (Older named "Norton") products, they NOW have a Complete Security package Including Registry Clean-Ups for Windows from XP-7 at very competitive cost! I used "Bit-Defender Antivirus" several years back because they were
the ONLY Few PPL having a 64-bit AV program available and Work to the highest standards for the price! They turned me on to "UniBlue" Registry Repair/Cleaner. Works Excellent! I transferred it from my Vista to Win-7-64Bit and ran like a charm! You won't
find it listed in "Affliate Review Sites", therefore ya aren't payin' the "Middle-Man"!
The prices are 'bout to the SAME.. BUT THe Computer Protection is TOP-OF-THE-LINE! Full Internet Protect and Reg-Cleaner combined - "Norton 360 Version5" (Includes AV and Internet!, Performs with LEAST SYSTEM NOTICABLE SLOWDOWN! Bout $60 for 1-3 systems),
a Super Reg-Cleaner (if that's all you're looking for, "RegistryBooster" 'bout $29 annually). Can't be beat!