title: Error when Connecting to SQL Server
body: <p>I was working with an instance of SQL Server 2012, but after updating my Avast (anti-virus)  I can't connect to that instance anymore and I have this error message:</p>
  
  <blockquote>
    <p>TITLE: Registered Servers</p>
    
    <p>Failed to connect to server . (Microsoft.SqlServer.ConnectionInfo)
    ADDITIONAL INFORMATION: A network-related or instance-specific error
    occurred while establishing a connection to SQL Server. The server was
    not found or was not accessible. Verify that the instance name is
    correct and that SQL Server is configured to allow remote connections.
    (provider: TCP Provider, error: 0 - Aucune connexion n’a pu être
    établie car l’ordinateur cible l’a expressément refusée.) (Microsoft
    SQL Server, Error: 10061) Aucune connexion n’a pu être établie car
    l’ordinateur cible l’a expressément refusée BUTTONS: OK "</p>
  </blockquote>
  
  <p>I just want to be precise that I have allowed all TCP/IP connection rules from my firewall system and each time I try to start the server from the SQL Server Management Studio it doesn't work :(   </p>
  
  <p>What should I do ?</p>