Does he REALLY like me?

I have a big problem and it’s starting to drive me mad not knowing the answer. I’m in love with a guy who goes at the same school as me. I see him every day but we’ve never talked to each other IRL, but we usually chat on MSN messenger, one or two times a week. The problem is that I don’t know if he wants to be more than friends. He almost never writes to me first, 90% of the times I’m the one who starts chatting with him. That you could maybe see as a proof of him not being interested, but it’s more complicated than that. He is kind of a shy guy. He rarely leaves his house, except for hanging out with his friends. He never goes to parties and he doesn’t drink alcohol. Most of the time I think, he spends in front of the computer, playing computer games and watching movies. I don’t know if he chat a lot with other people than me since he sits a lot in front of the computer, but I doubt it. He has for example always his status set on idle and expects people to write to him anyway. But why do I think that there’s a chance that he’s interested? When we talk to each other he’s nice most of the times, and I hope that he enjoys talking to me. Even though he rarely writes first I’ve noticed that if I wait a while and don’t write for like two or three weeks he writes to me eventually. But then if he likes me, why does he write to me so seldom? Is it because he’s shy or isn’t he really interested? Is he just writing to me when he’s BORED or something? When we are in school and we meet each other, he never ( and then I mean never) looks at me. But I sometimes see his friends look at me like if he had said something about me, but I don’t know if I’m just imagining it. And if he has, I don’t know if it’s positive things or if they’re just laughing at me behind my back. (thinking I’m desperate and so on) He knows that I’m interested, I’m sure. I’ve given him compliments and I give him attention by writing to him. My question is whether he is interested in me? Is he just shy or isn’t he interested the way I want him to be?
Please answer! I’m desperate to know. / Ella