What should I do about my friend...BIG PROBLEM!!!

My friend Samantha told me that she hates my ex Kris, but the other day my b/f John saw them hanging out...They said they were going out...the only problem is that my friend already has a b/f. I've been trying to tell my friend that her b/f Paul would be really mad if he ever found out...(he's in jail right now)...but it just doesn't seem to sink in... Also Kris is telling her to stop talking to me and my b/f and our friend James because he thinks we are all loosers...And Kris told my b/f that he only wants to date Samantha so he can take her SSI check when she gets it...We've tried telling her that and all she said was that she wasn't going to give him any money because she needs it...But she used to give him money all the time (before they were even going out) and she always ysed to say the same thing, but she never did it...What do I say to her to try to get some sense into her?