With the friend-zone thing -- I can imagine a couple of scenarios.

1. The girl is interested. You chat. No one makes a move. The next day the same thing happens. She figures you aren't interested. The third day, she treats you as if you are not interested.

2. You chat. She isn't interested in you romantically but senses your interest in her. She starts telling you about her boy trouble to let you know she isn't interested.

There are a ton of other scenarios, but until you are more direct about your romantic interest, you will never know what is going on. When you meet a girl you like, I would directly indicate interest by the end of the first or second conversation. By direct, I mean asking her out on an obviously romantic date i.e. dinner and a movie or offer to buy her a drink. If she shows interest, nail down a time and a place immediately.

You have nothing to lose, right? You aren't looking for another friend, so if she says no, just move on. Don't waste your time being bored to death by their problems, unless they show you the same courtesy.

It sounds like you got to be pretty close with that other woman, so that's proof it's possible - you just have to find the right one.

It takes A LOT of misses before you get a hit. Dating can be horrible. I agree with the advice above, too -- and improving your physical appearance is huge. My dating pool increased ridiculously when I lost 25 lbs.