I actually used to like this I'd say 7 months ago. Now it's been a year. She already has a boyfriend but for some reason I STILL like her? Even though knowing it's all done. She told me that she doesn't like me more than a friend, what do I do? For some reason my situation is, even though NOT WANTING to like this person I still do? I mean I know everything, I know I don't have a chance, I don't want to like her but I do?

You choose to move on. Do you want to be miserable?
Hang out with friends make new ones. She is not the only girl in the world.
Sounds like you've become obsessed with her. Are you this way with other things?