Is it possible? i have already erased every entry from windows registry using regedit, reinstalled ccleaner, and it keeps appearing. I would greatly appreciate any help .
Sadly, Firefox is one of the ones that uses a special key for CCleaner to detect it (as opposed to a file or registry entry that is user accessable) however I would try the following
Make sure you've no more Mozilla Products installed (Songbird, Thunderbird, old emusic downloader etc) then make sure that there is no Mozilla Key in your registry and no mozilla folder in %Appdata% or %programfiles%