title: C# Program can only run once + BringToFront if started a 2nd time
body: <p>I want my program to be startable only once (it doesn't matter if it can be started on other user-accounts).</p>
  
  <p>If its already started and the .exe is opened again it should bring the main-window of the first instance to the front.</p>
  
  <p>What's the easiest way to achieve this?</p>