Here i am going to write the method to make your trojan, keylogger and RAT FUD (fully undetectable) by antivirus softwares.

1- Download PC Guard For Windows 
2. Open PC Guard , and in the "Application filename" browse your server's location.

3. Click on the "General" tab, and check the options like on the image below.

3. Now do the same with the "Security & Encryption" tab. Look at the image below to see what options to check

4. At the end choose "Protection Methods", and select the following options:
You have done it....

Now your server, keylogger is FUD(Fully undetectable) from antivirus and other security tools.