Need Help to stop child from hitting me

Thank you for your responses. I fully realize what will happen when he gets older and I can no longer carry him or hold him to stop the hitting. That is what scares me. We find ourselves wondering often if we have made a terrible mistake in adopting him. We were told that he was this sweet boy that we would need to bring out of his shell and his is not that at all. I fear of what the future brings when 1 1/2 years with us has made some improvements, but not enough. We definitely do not reward him for that behavior, but he does not seem to care. When we try to talk to him he just screams and will not listen. If we are home when this happens, we send him to his room to calm down and then try to get him to tell us why he was sent there. We do not always have much luck with getting an answer. Thanks again for your input. Julie