title: Can't activate Visual Studio with product key
body: <p>To be short: 
  What do to if you have a Visual Studio product key, but can't find how to activate it?</p>
  
  <p>In my case this was VS 2017 Professional. </p>
  
  <p>I was triying to find how to activate VS. After few unsuccesfull attempts I've Googled for it and <a href="http://sanderstechnology.com/2017/visual-studio-2017-using-a-product-key/15163" rel="nofollow noreferrer">found</a> that there must be a "<strong>Unlock with a Product Key</strong>" button. </p>
  
  <p><a href="https://i.stack.imgur.com/kakCW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/kakCW.png" alt="Activation window"></a></p>
  
  <p>But in my case there wasn't such button. I had absolutely the same window just without "Unlock with a Product Key" option.</p>