So I played this game around when it first came out and around chapter 5 I just kind of stopped playing it. I told my roommate tonight that I need to finish it. I enjoyed the game and I don't know why I stopped playing it. Here is the problem, I'm fighting from what I can remember a regular mob. How the hell do you kill them again? I shot off the legs the arms the head and 60 bullets later it's still not dead. I really can't remember what you are supposed to do...

It sounds like you might be at the part where you meet the regenerator monster, and are supposed to run away rather than fight it.  Took me forever to figure that out too.  You'll meet it a few times throughout the story before you can finally get rid of it for good.

Run and eventually you have the chance to freeze it.