Config config = new Config()
Auth login = new Auth(config)

public Auth(Config config)
{
 ....
}
public void checkAuth()
{
...
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.IO;

        /*
         * MD5 Hash
         */
        public static string GetMD5Hash(string pathName)
        {
            string strResult = "";
            string strHashData = "";

            byte[] arrbytHashValue;
            System.IO.FileStream oFileStream = null;

            System.Security.Cryptography.MD5CryptoServiceProvider

Index was out of range. Must be non-negative and less than the size of the collection

try
                {
                    lblStatus.Text = "Installing...";

private void DoDownload()