1) it should appear in your Ccleaner's tools --> uninstall page, but please try and check if Assassins creed is there first before trying step 2. Ccleaner --> Tools --> Uninstall
2) Go "Computer", Double click on "Local Disk" and delete Assassins creed from either "ProgramFiles or ProgramFiles (x86) or even both?!
3) Press start on your windows, where it says "Search programs and files" Type in %appdata% and if you see it there, also delete it. (this would be it's cache)
and 4) go back into that search bar from step 3 and type in "Regedit", and try and locate Assassins creed there, ("mostly on users tab") and delete it from there.
This would get rid of Assassins creed completely manually.
no like problem is i uninstalled assassins creed black flag long before now i wanted to play it again so when im trying to install it UPLAY is saying first i need to uninstall the game but i did long back. so when i checked in google they were like use Ccleaner to uninstall it completely but how ?