my 4 year old has turned into the devil


Can anyone give me some advice about my little girl?
My 4 year old abbie was always such a little angel but where has she gone?
First of all her behaviour is sooo bad and it used ot be so good.She bites,scratches,kicks,throws things about,breaks anything she can get her hands on,bullies her two year old brother so much that he now mimics her behaviour,she snatches anything her brother has and claims it as her own,she ignores anything you say to her including when you tell her off,she scolds you for telling her to do what she is told and she laughs in you face for telling her off.
i have tried everyhting except smaking her and i am at the end of my teather with her.Has anyone got any words of wisdom for me?PLEASE hELP ME!!!!!
its definitely a 4 year old thing - vanyas posted about this earlier - some great tips here....

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