title: Are .OCA files necessary for program execution?
body: <p>In the <code>system32</code> directory I saw an <code>.OCX</code> file with a corresponding <code>.OCA</code> file.</p>
  
  <p>I had thought <code>.OCA</code> files are used only by Visual Basic. Are they therefore unnecessary for program execution and could be removed?  </p>
  
  <p>If they are unnecessary, why would there be an <code>.OCA</code> in the <code>system32</code> folder in the first place?</p>