Knocking in engine

My question is will the engine turn over or is it locked up? If it turns over but will not start you could have had an oil pump fail and burned you pistons. If that is the case replace the whole engine as in the long run it will cost just as much. If it will not turn over at all then the engine is locked up for the same reason above Still I found that it was cheaper to replace the whole engine in my Eclipse than to fix the old one.