Heavy flirting with girl at work with genuine stares and smiles. I could tell she was flattered and would give me Long stares when leaving work. I asked her out but turned me down. And I played it cool and told her maybe next time. And she stood there and smiled like she was waiting for me to keep asking her questions but I pretty much left the conversation there so she walked away . Before she left worked she said goodnight and stated at me as usual. What. Gives?

She may have a boyfriend and that's why she is saying no.
Or maybe she likes having you chase after her some women like being chased after.Keep in mind some people love playing mind games too it could be any of these things.
So I hope this helps some and good luck.
One more thing if she keeps saying no then find another woman.

As a female, we make look at a guy and be flattered when he flirts but it does not mean we want to date you. This what this sounds like to me. She said No, now move on.

I believe she has a boyfriend.I She came to my desk twice and asked me "SO what were u going to ask me?" She seemed to know I was going to ask her out and she was ready for the no. So silly. She even leaned over my desk when she did. Lol Ive caught her staring at me several times getting nervous when I looked over. Why turn me down and give me a smile from ear to ear? Ugh. I know Im to move on if she is determined in her world but I really like this girl more and more every time I see. Why are girls so indecisive and play these games. She fights for my attention and then drops the ball when I move. o_O

"SO what were u going to ask me?" She seemed to know I was going to ask her out and she was ready for the no.

Now I'm confused. In your original question, you said you asked her out and she turned you down. Now it seems as if that was incorrect...

Move on dude. Especially if she has a boyfriend.