Does he like me?

I really really need some advice. Boys, if you're reading this, maybe you might understand and if yes please tell what I should do.
There is this guy, I'll call him K. I've never talked to him, but we have mutual friends. He isn't in any of my classes.
I noticed that he glanced at me a lot when we would pass each other in the hallways, and I didn't really think about it because I am not the type who thinks about guys. But then I started to be interested and asked my friends about him. Now I know a lot about him, and I think he also knows some things about me because I have the reputation for being very smart.
This has been going on for almost two years now! For two years we've been staring at each other like two idiots. I've tried to talk to him, but he always goes away before I can say a word. Once when my friend was talking to him, I went up to her, and he said goodbye and walked away from us.
Now, I am actually wondering if he likes me or not. It is really annoying because just before the summer holidays he got a girlfriend. (Who skips lessons, all she does all day is spread rumours and bully other girls) I've never talked to K, but I know that she doesn't deserve him. I saw how she treats him and it's horrible.
Now a new school year begins and I just want to forget about him (I've tried this already but I couldn't). I just want to get on with my work and forget about him because I feel like I am wasting my time and energy with him. I know K's relationship with that girl won't last, my friend told me how horrible she is to him and K won't accept that.
The only thing I want to know is: Did he like me or was he staring at me because he had nothing better to do?

If he still has a girlfriend, regardless of what you think she's like, the answer to your question doesn't matter.

I think they broke up because I don't see them together anymore and I saw the girl crying the other day.
And the question really matters to me...

Ask him. No-one else is going to know...