Hello:
I ran CCleaner 2.30.1130 on win xp sp3 and it did not detect keys like these:
HKEY_CURRENT_USER\Software\ESET\OnlineScanner\Path
Data: C:\program files\ESET\ESET Online Scanner\
[ESET was uninstalled, folder does not exist anymore]
HKEY_LOCAL_MACHINE\Software\Microsoft\Internet Explorer\Low Rights\ElevationPolicy\{C8FE2181-CAE7-49EE-9B04-DB7EB4DA544A}\AppPath
Data: C:\program files\Java\jre6\bin
[Java was upgraded, folder does not exist anymore]
HKEY_CLASSES_ROOT\Installer\Products\12F610CC0793ED118B87000565084666\SourceList\Net\1
Data: C:\DOCUME~1\admin\CONFIG~1\Temp\7ZipSfx.000\
[.net framework update, but installation folder is temp, it does not exist anymore]
HKEY_LOCAL_MACHINE\Software\Microsoft\Updates\Windows XP\SP4\KB956744\UninstallCommand
Data: C:\WINDOWS\$NtUninstallKB956744$\spuninst\spuninst.exe
[Windows update, uninstall source seems to have been deleted by ccleaner, but not in registry!]
I have hundreds of these kind of entries... I suggest CCleaner could be run with an "advanced option" in order to detect wong paths to inexistent files. User would be responsible of deciding if deleting that stuff.