If it has been proven that a man is not the father of the child, how long does he have and how does he go about getting his name removed from the birth certificate in Florida?

You will need a court order to remove your name from a birth certificate. I don't know if it's possible to do this without an attorney, personally, I'd take the dna results to the court house and ask if you can have your name taken off the birth certificate. They will be able to tell you if you need an attorney or if you can schedule a hearing to have your name removed from the record.