Can't get rid of a Trojan.zeroaccess.inf4 virus and my email has been hijacked. Please help!!!

I have spent two days scanning and trying to get rid of this virus from my computer using Norton Eraser, Norton 360, Malwarebytes and Spyhunter and it doesn't matter what I do, I keep getting the message that I have a Trojan.zeroaccess.inf4 virus. And that it requires manual removal. I look up how to remove it and Norton suggests Norton Eraser  - but Norton Eraser does not detect it.  My email is sending out spam to all of my contacts every hour.  PLEASE HELP!