Work Problems

I know I posted the other day about one of my coworkers not wanting to talk to me. I've been waiting around since then hoping that she would snap out of whatever her funk is. Good thing I haven't been holding my breath.
I went so far as to ask yesterday if anything was wrong. She said no.
But I can't help but think that I've done something to bother her, even though I can't think of anything. I come into work and try to give 150% to my job. I make a point to do my job to the best of my ability, and I try to do more. I try to make sure that everyone in the office has everything they need to do their jobs well. And I try to make sure that my boss remembers everything that we need.
She's been a little better today. A couple of times she has even answered my questions at something approaching a normal volume. But she still isn't saying more that absolutely necessary to answer my questions. She isn't really responding to my efforts to involve her. But she sure will talk and joke a little with some of the other people in the office. I heard her picking on a couple of the techs earlier.
But after the bossman asked me a couple of questions earlier that I answered (and that she could have easily put her input into without seeming to butt in or be an ass) I saw her pass him a couple of dirty looks when he wasn't paying attention. I know that she isn't particularly happy with him being the boss. She kinda wanted to be the boss, or at least keep our previous one. And I know that she isn't particularly happy with her job (and is semi looking for a new one). But why is she treating me this way? Why won't she just tell me what I've done to make her try to ignore me to the best of her ability? It's not exaclty comfortable to work in an office where the only other female apparently hates you. I know, because that is how she has been making me feel. And I think it's starting to affect my performance. I hope she snaps out of this soon. Because if she is still this way next week, I will have to talk to the bossman about it. Robin might not want to have to deal with a disgruntled employee, especially one as obvious about it as her, but it has to be dealt with eventually. And the sooner the better.