using System;
using System.Text;
using System.Diagnostics;
using System.Security;
using System.Reflection;
using System.IO;

namespace ConsoleApplication6 {
    class Program {

        unsafe static void Main(string[] args) {

            Process process = new Process();
            String dir = Path.GetDirectoryName(typeof(Program).Assembly.Location);

            String txtFile = Path.Combine(dir, "example.txt");
            if (!File.Exists(txtFile)) {
                StreamWriter sw = File.CreateText(txtFile);
                sw.Close();
                sw.Dispose();
            }

            ProcessStartInfo info = new ProcessStartInfo();

            info.Domain = "myDomainName";
            info.UserName = "userName";
            String pass = "userPassword";

            fixed (char* password = pass) {
                info.Password = new SecureString(password, pass.Length);
            }

            // Will be run notepad.exe
            info.FileName = Environment.ExpandEnvironmentVariables(@"%winDir%NOTEPAD.EXE");
            // in notepad.exe will be open example.txt file.
            info.Arguments = txtFile;
            info.LoadUserProfile = false;
            info.UseShellExecute = false;
            info.WorkingDirectory = dir;

            process.StartInfo = info;
            process.Start();
        }
    }
}