Batman Arkham Asylum Help

[SupahKat]

I have downloaded the Arkhum content (NCF and common folder) and have placed in required places. It shows up in my cracked steam, but when I launch the game it asks for a serial number. Well....obviously I don't have one. Is there any way to get past this? I really want to play this game.

--edit

Got it working thanks to a crack from a friend in another forum.