How do i deal with a psycho ex girlfriend?

seniors in high school i broke up with her about 4 months ago. even up until now she tries to brutally scare and threaten any girl that i talk to. she knows how to hack into my myspace and figures out all my conversations. she claims that the reason she hares the girls have nothing to do with me which cracks me up. she's constantly trying to gain my attention by hanging out with all my friends, and also having with other guys to make me jealous. We talked on and off for a while because she tried luering me in with the whole "friends with benefits deal" but that didn't work to well because she begged for me back and thought i would go for the bait. so i started ignoring her completely just as i did when we broke up and all the chaos started again. What is the best solution to get this whole thing to die down. Oh and she's constantly slandering me on myspace so everyone can see saying really mean stuff and tries to turn my friends against me . But in the end...she acts like she hates me haha which is hilarious. please help me thankyou so much..