1) she really wants to be president and just can't quit.
2) she needs to raise additional funds to pay off her debts before she drops out.
3) she really feels like she can still win.
4) she's going to try and push herself as vice president.
5) her ego is too large to let her drop out.
6) she wants to go out on a high note with west virginia.
7) she'd be bored if she quit.
8) she's bought the superdelegates.
i can't think of anything else.
here's another thing. i don't think hillary has educated her supporters on the delegate process. many seem to think she still has a shot, which leads me to believe that #2 is the reason she's staying in. after she sucks up her supporters money, and after west virginia (maybe kentucky), she'll bow out.
here's another thing, looking at her blog, her supporters seem to relish the "fighter" psychology. nearly every post has the word fight, fighting, fighter. hillary against the media! hillary against BO! hillary against the world! never give up!