此PHP PDO代码无法正常工作。无法知道为什么？

Question

我是PDO的新手，也是初学者。伙计我无法找到我写的代码中的错误。如果您可以帮助我完成此代码，那将是一个很好的帮助。

<?php
$UserName=$_POST["uname"];
$Password=$_POST["pass"];
try
    {
        $con = mysqli_connect("localhost","TechicalClass","King","Database") or die("connection not established!!" .mysqli_connect_error());    
        $sth = $con->prepare("select Hash from LoginInfo where UserName = :username") or die("Died in Preparing");
        $sth = bindParam(':username',$UserName) or die("Died in Binding");
        $sth-> execute() or die("Died in Execution");
        $user= $sth->fetch(PDO::FETCH_OBJ) or die("Died In Fetching");
        echo hash_equals($user->hash, crypt($Password, $user->hash))."</br>";
        if ( hash_equals($user->hash, crypt($SPassword, $user->hash)) )
            {
                echo "<img src='correct.png' height='25px' width='25px'/>";
            }
        else
            {

                echo "<img src='wrong.png' height='25px' width='25px'/>";
            }
    }
catch(PDOException $e)
    {
        echo "Error :".$e->getMessage();
    }
  ?>