How long have you known her? If only for a short period of time, it may just be her true personality finally coming to the surface. If you've known her for a while, and feel that your relationship is strong enough to give her real, strong, constructive criticizm, then tell her that she's making herself look like an idiot. Tell her that other people at work have been talking about her. Tell her how it makes you feel to see her screwing up like this. Perhaps she is just tired of the job and taking it as a joke now. Maybe she just needs a career change, who knows. If she's truely a friend, she should be able to take your advice rather than blow it off and ignore you.