I am not sure what your problem is.

You have received the right responses from several people here already.

"So what if I let my friend "steal" some letterhead of the company I work for."

Sorry, but aren't you stupid or what? Conspiracy is a crime, get it?

You are desperate for what? For knowing that is rignt and what is wrong and still wants to do the wrong thing and not get caught? What a loser.