How can I contact my dead friend?

before saying something, no this question is not in yahoo answers, in a clear way.......ok here's the thing: this past Wednesday a friend of mine and many people more suddenly died of a respiratory problem when she was sleeping, she was in perfect health by the way. Now i want to contact her, because I feel she doesn't know what happened, and I want to talk with her and explain her that everything it's ok, that shes dead, and that she can rest in peace, knowing that everyone its relaxed with that, she once told me that when she died She doesn't want anybody suffering, but maybe shes the one that it's suffering because she doesn't know what happened, anyone, got an answer, please religious fanatics get out of this topic and promote you crap in somewhere else, Science it's my law, and not a children's tale for ignorants, I just want a clear answer, proved by somebody, or a good negation.