Eliminate Trojan:Win64/Patched.AZ.gen!dll Completely From Infected PC

I foolishly picked up a Trojan virus (Trojan:Win64/Patched.AZ.gen!dll) on my media PC a few nights ago and, after some battling, managed to remove all the software it added, and regain access to the internet. However, I was unable to remove the virus from the dnsapi.dll file. Please anyone help me?

Trojan:Win64/Patched.AZ.gen!dll Description

Trojan:Win64/Patched.AZ.gen!dll is a severe Trojan infection that can affect many Windows computers. It is often distributed via spam emails, pornographic websites, free application downloads, and other social network services. So this Trojan horse usually invades your computer without your knowledge. Once you find it in your computer, you should take immediate actions to deal with it or it will seriously damage your system.