Iv'e been investigating the virus issues some people have been having and I think I have found how people are getting virus's from an expert advisor files. I have seen that some of the EA's from infected computers are running a block of code like this

#import "shell32.dll"
int ShellExecuteA(int hwnd,string lpOperation, string lpFile,string lpParameters,string lpDirectory,int nShowCmd );
#import

void pop ( string msg , string installed_dir)

{
ShellExecuteA(0,"Open" ,"xxxxx.exe",msg,installed_dir,1);
}

This is particualry worrying as it means that your EA is running an executable file which could potentially infect your computer

I have also purchased MT4 Protect, Its an antivirus program that I found aimed at MT4 Traders. After talking to the developers of that software I am confident that it will protect my machine from these type of EA bourne virus's. It is based on the ClamAV virus engine which is updated multiple times a day and used by some of the biggest organzations in the world.

My advice is to not run any decompiled EA's that you get from dubious sources.