$ID = intval($_POST['ID']);
        $nome = nl2br( addslashes($_POST['nome']));
        $email = nl2br( addslashes($_POST['email']));
        $user = nl2br( addslashes($_POST['user']));
        $password = nl2br( addslashes($_POST['password']));


      $existe = ("SELECT * FROM utilizadores WHERE username LIKE '".$user."'");
      $faz_existe = mysqli_query($existe);
      $num_registos = mysqli_num_rows($faz_existe);

      if($num_registos==1){
          header("Location: ../login/registar.php?erro=1");
      }else{
          $query = sprintf("INSERT INTO utilizadores (id, nome, email, username, password, acesso) VALUES ('%s','%s','%s','%s','%s','2')", $ID, $nome, $email, $user, $password);
          $pv = mysql_query($query);
          header("Location: ../login/");
      }