title: Start only one instance of MFC Dialog Based Application
body: <p>I have created a MFC Dialog Based application. </p>
  
  <p>I started the application and it worked fine. Now, while it is running, I start the application again, and it starts another instance of it. </p>
  
  <p>But, I do not want his behavior; If the application is already running, I want to prevent that new instances of it will be created.</p>
  
  <p>Please, give me the code.</p>