Please help! I have no idea what to do!?

Last year in first hour there was this really weird kid who sat behind me. But I was nice to him and we played hangman if we finished our work early. Well I really hadn't talked to him this year until I got a facebook. Now he comments on every single one of my statuses even if they would have nothing to do with him, and he IMs me ALL the time. Even if I'm not responding. Now the thing is I don't want to be mean to him because a person's a person, and he has feelings, but I don't like him constantly... bugging me. I don't mean to be stuck up, but it's got to the point where I'm not on facebook for more then a second because he'll be commenting on anything I do. I have one cl with him (Health) and every once in a while he will say something to me, but he really doesn't talk to me in person. Any advice is greatly appreciated!