Dating at work is very different than dating out of work. It all depends on your position in the office. People are constantly watching you and talking about you, so a girl has to be careful who she even talks to in the hall for a brief second. People will assume you are banging or have something going on. Thats why a girl will get to know you quickly, then shut you out like a leper to avoid anyone thinking you have something going on together.
At the office the key players usually benefit from very overt or noticeable benefits they receive (good office, parking, power). This stuff is candy for women, drives them nuts. Women will throw themselves at you if they see you are one of the top dogs of the office like that, even if you are a complete a s s h o l e. It seems to attract them even more if that makes any sense. These guys can pick what girls they work with, who she sits next to, and who to fire if they get too close to a girl they like, and nobody will ever know their true motives. A fine woman will usually try to make herself seem as available to these guys as possible. And so will avoid being seen with you too much or at all if her sites are set so high.
How I personally handle the office hookup:
Be aloof and unaccepting, don't treat anyone like your friend. Just because she's pretty doesn't mean she's cool. If a girl has a technical problem be very open in your conversations with her. Bring other people into your conversations when you can so everything is very public and clear there's no hookup going on. People at the office just love pop culture, watch "Breaking Bad" or something so you have something to talk about that is relevant to what everyone else is talking about.
If you establish a good enough rapport with her and the topic of things done after work comes up always speak in secrecy and hushed tones. You don't want people to know or suspect you are hooking up or hanging out. If she asks just tell her you don't like people at the office knowing your business or personal life. You don't want undesirables infiltrating your group. You don't want her to worry about this stuff either. You want to make her feel special, like you are letting her in on some awesome secret club where coworkers let their hair down and party like animals.
As soon as you get her out in private game her like usual. If she is not receptive cut her ass off completely. She's obviously an idiot for letting things go this far with someone she does not have interests in. She's confused about you and she is going to be confused about other things as well, you don't want an idiot in your crew blabbering about the things you do after work to everybody else just to have something to talk about. And she will...
