สอบถามเรื่องการหยุด process ที่ทำ มือใหม่ C# ขอถามจากผมได้ดึง exe มาโดยที่อยากหยุด process

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Threading;
using System.Diagnostics;


namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Process p = Process.Start("test_nor.exe");
            Thread.Sleep(1000);
        }
        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        public static extern IntPtr FindWindow(string classname, string windowname);
        [DllImport("user32.dll")]
        public static extern bool SetForegroundWindow(IntPtr p);
      
            

        private void button2_Click(object sender, EventArgs e)
        {
            
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }

        private void button3_Click(object sender, EventArgs e)
        {
            this.Close();

        }

        }
    }