杀线程的代码（转自CSDNcyfboy）

private void KillProcess(string processName)
        {
            System.Diagnostics.Process myproc = new System.Diagnostics.Process();
            //得到所有打开的进程
            try
            {
                foreach (Process thisproc in Process.GetProcessesByName(processName))
                {
                    if (!thisproc.CloseMainWindow())
                    {
                        thisproc.Kill();
                    }                    
                }
            }
            catch (Exception Exc)
            {
                MessageBox.Show(Exc.ToString());
            }
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            String tempName = "";
            int begpos;
            int endpos;

            foreach (Process thisProc in System.Diagnostics.Process.GetProcesses())
            {
                tempName = thisProc.ToString();
                begpos = tempName.IndexOf("(") + 1;
                endpos = tempName.IndexOf(")");
                tempName = tempName.Substring(begpos, endpos - begpos);
                //this.listBox1.Items.Add(tempName);
                if (tempName == "newfax")
                {
                    KillProcess(tempName);
                }
            }
        }