Form1.cs

using System;
using System.Diagnostics;
using System.IO;
using System.Reflection;
using System.Windows.Forms;

namespace HL2_Cinematic_Mod_Launcher
{

    public partial class Form1 : Form
    {
        private ToolStripMenuItem _fileToolStripMenuItem;

        public Form1()
        {
            InitializeComponent();
        }

        public void Form1_Load(object sender, EventArgs e)
        {
        }

        string _gameDir = null;

        private void button1_Click(object sender, EventArgs e)
        {
            var myDir = Path.GetDirectoryName(Assembly.GetEntryAssembly().Location);
            if (myDir == null) return;

            if (string.IsNullOrEmpty(_gameDir))
            {
                MessageBox.Show(@"Please select the Cinematic Mod installation directory first");
                return;
            }

            var gameExe = Path.Combine(_gameDir, "Configurator.EXE");
            var proc1 = new Process
            {
                StartInfo = { FileName = gameExe, WorkingDirectory = _gameDir },
                SynchronizingObject = this,
                EnableRaisingEvents = true
            };
            proc1.Start();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            var myDir = Path.GetDirectoryName(Assembly.GetEntryAssembly().Location);
            if (myDir == null) return;

            if (string.IsNullOrEmpty(_gameDir))
            {
                MessageBox.Show(@"Please select the Cinematic Mod installation directory first");
                return;
            }

            var gameExe = Path.Combine(_gameDir, "Launcher_EP0.exe");
            var proc2 = new Process
            {
                StartInfo = { FileName = gameExe, WorkingDirectory = _gameDir },
                SynchronizingObject = this,
                EnableRaisingEvents = true
            };
            proc2.Start();

        }

        private void button3_Click(object sender, EventArgs e)
        {
            var myDir = Path.GetDirectoryName(Assembly.GetEntryAssembly().Location);
            if (myDir == null) return;

            if (string.IsNullOrEmpty(_gameDir))
            {
                MessageBox.Show(@"Please select the Cinematic Mod installation directory first");
                return;
            }

            var gameExe = Path.Combine(_gameDir, "launcher_EP1.exe");
            var proc3 = new Process

            {
                StartInfo = { FileName = gameExe, WorkingDirectory = _gameDir },
                SynchronizingObject = this,
                EnableRaisingEvents = true
            };
            proc3.Start();
        }

        private void button4_Click(object sender, EventArgs e)
        {
            var myDir = Path.GetDirectoryName(Assembly.GetEntryAssembly().Location);
            if (myDir == null) return;

            if (string.IsNullOrEmpty(_gameDir))
            {
                MessageBox.Show(@"Please select the Cinematic Mod installation directory first");
                return;
            }

            var gameExe = Path.Combine(_gameDir, "Launcher_EP2.exe");
            var proc4 = new Process

            {
                StartInfo = { FileName = gameExe, WorkingDirectory = _gameDir },
                SynchronizingObject = this,
                EnableRaisingEvents = true
            };
            proc4.Start();

        }

        private void button5_Click(object sender, EventArgs e)
        {

            var fbd = new FolderBrowserDialog
            {
                Description = @"Please select the Cinematic Mod installation directory."
            };

            if (fbd.ShowDialog() != DialogResult.OK) return;

            {
                _gameDir = fbd.SelectedPath;
            }
        }

        private void exitToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Close();
        }
    }
}