Confused; What does she really think?

Hello.

There's something that has been bothering me for several years.
In my class there's this girl. I wonder how I should explain the situation...
Well, you see, several years back, we talked once in a while, not that much though. I started to really like this girl, and I told that to a couple of friends, who told it to her.
She didn't like me though.

Now, it wasn't really a problem for me. If she doesn't want to be my girlfriend, it's okay. We'll still be friends, right?
Wrong. We hardly talked anymore after she got to know I liked her. In fact, she seems to have become hostile or something.
I've mailed her several times, and tried talking with her on MSN, but every time I try this, she sais something like "I don't want to talk with you" or something like that. I once wrote a pretty long mail with some help of a friend, so it would be perfect. I explained how sorry I was for, well, whatever I did to her, and that I'd like to know what's wrong and stuff like that. She mailed me back that she really doesn't want to be friends with me, simply because she 'has friends enough'.

I gave up. How could this ever be rectified? She seems to hate me. I probably screwed up somewhere.
So, you'd think I'd just forget about her, right? Well, I can't. Somehow I just can't. Even when I think I forgot about her, she returns in my dreams. It's really troubling me that I don't know what's wrong, what I did to her or whatsoever.

I feel really confused about this all. You see, whenever I get to talk to her in real life (which isn't that often though), she's nice and friendly. We sometimes even laugh together. At moments like these I feel as if those mails weren't written by her, how could those words possibly come out of her mouth? This is mostly when we're alone and there's nobody else around. Could it be that she doesn't want her friends to see her talking with me?

I sometimes just wished that I could get a moment alone with her, just to talk and gain some knowledge. I just want to know what's going on. Even if she tells me she really hates me, loathes me or whatever, at least I know the truth. Right now, I don't know what to think. Is her smile real, or is she acting? Or perhaps she's scared of something?

Can someone explain this? It's so weird, and I feel so confused. On one hand it seems like she hates me, but on the other hand we can have really nice talks and laugh, look at eachother and stuff.

I'm sorry if this post is a bit vague... The whole situation is vague XD