HELP ME PLEASE WITH MY 31/2 YEAR OLD

Help! My daughter will be 4yrs in April. . I have been having problems with her behavior for about 2 months now. When I try to correct her she gets violent. She throws things around the room, at me and her baby brother who is 8 months. She hits me, slaps me, grabs at my clothing, screams, slams doors.. I even threaten her with a spanking(some times it gets to that point, it still doesn't help). There's only so much I can take. I'm a stay at home mom, so I'm with her all day.. I'm afraid for her to start pre-school or even take her to day care because of her behavior.. What can I do to get her to stop being so mean to me and her brother.... I have no one else to turn to.  

[margypops]

What started this behavior did she have some trauma for it to appear so suddenly,and what happens prior to this behavior as perhaps something triggers it.Her brother is only 18months old, it is possible she could use some positive attention from you, sometimes children feel left out when a sibling arrives and maybe you could focus on her , try a lot of Physical activities and sports and Games . if Dad is around get him involved helping with some outside fun.

[kennedysmomma]

Kennedy just started this behavior.. and what triggers it .. is her not getting her way . alex is 8 months well i think i seem to give them both the same attention. i try my hardest not to spend more time with either of them.. i try to make it equal amount of attnetion. but you know what i was thinkin.. we have a friend staying with us .. and well he has been her for about 2 months.. i dont want to think bad about him.. but could he be touching her??? i wonder.. whats are the signs

Amy.. kennedys mom