Hits herself when angery!!!!

Please help,
        My daughter is 5 years old, when I tell her NO or you cant do this right NOW or You have to sleep in your room. she trys to cry and wine her way into me saying yes then she has started to hit herself and i mean she is hiting her self hard and she has even told me that she wants to "just hurt myself" what do I do??? Im lost?? She is a great little girl but when she doesnt get her way she turns into a different kid but like all parents know we have to set rule and we have to say no. Now i know when to pick and chose a battle. Can someone please give me some advise on how to handle her when she starts to hit herself.

Thanks,
   katrinarose   lost for words

[puprock97]

Personally, I would hold her when she hits herself. Like hold her arms so she can't hit herself. And look her into her eyes and say "Don't hit yourself. I am your mother and you are to do what I say. Understand?" See where that gets you.