Registry Cleaner is a member of a broad class of pesky, bogus antivirus programs.
This tool actually removes the whole family:
http://siri.urz.free.fr/Fix/SmitfraudFix_En.php

This tool removes Desktop Hijack malware: AdwarePunisher, AdwareSheriff, AlphaCleaner, Antispyware Soldier, AntiVermins, AntiVerminser, AntivirusGolden, AVGold, BraveSentry, MalwareWipe, MalwareWiped, MalwareWipePro, MalwareWiper, PestCapture, PestTrap, PSGuard, quicknavigate.com, Registry Cleaner, Security iGuard, Smitfraud, SpyAxe, SpyFalcon, SpyGuard, SpyHeal, SpySheriff, SpySoldier, Spyware Vanisher, Spyware Soft Stop, SpywareQuake, SpywareKnight, SpywareSheriff, SpywareStrike, Startsearches.net, TitanShield Antispyware, Trust Cleaner, UpdateSearches.com, Virtual Maid, VirusBlast, VirusBurst, Win32.puper, WinHound,