C#

Process[] processlist = Process.GetProcessesByName("Notepad");

foreach (Process theprocess in processlist)
{
theprocess.CloseMainWindow();
}

void CloseApplications(void)
{
  string explorerPath = Path.GetDirectoryName(System.Environment.SystemDirectory);

         explorerPath = Path.Combine(explorerPath.ToLower(), "explorer.exe");

  Process[] processes = Process.GetProcesses();
  foreach(Process process in processes)
  {
      try
      {
           if (process.MainModule.FileName.ToLower() != explorerPath)
                process.CloseMainWindow();      
      }
      catch
      {
           // Handle exceptions here.
      }
  }
}