Mega uninstall problem!?

i installed crysis 2, and had fun with it for a while. Then, with a major lapse in judgement, decided to delete the game folder from my program files lol. HUGE mistake! i then went about the horrendous task of trying to uninstall a deleted program... to no avail. i then used regedit.exe to delete all registry files pertaining to crysis 2, which i did still to no avail lol. i've about given up on fixing this problem. and it gets worse, after going about deleting all registry files i discovered that the game no longer showed up as an installed program in ccleaner, i thought i was finally done. nope! lol i tried to re-install the game and the installer claims that its still installed. what the hell! Please if anyone can help me i would be extremely appreciative. thanks.