Admin Authentification et supprission des utilisateur

Bonjour,
J'ai crée des page php qui permet de "Login & singup"
et je voudrais quand l'utilisateur de type "admin" dans la base de donnée connect il peut supprimer les utilisateur et sinon quand un utilisateur de typle "simple" dans la base de donnée il est juste capable de ajoutez des commentaire.

Voici les codes :

SINGUP

<link rel="stylesheet" href="style.css">
<center>
<div id="signup">
<h3>Registration</h3>
<form method="post" action="inscription.php" name="signup">
<label>Name</label>
<input type="text" name="T1" autocomplete="off" />
<label>Email</label>
<input type="text" name="T2" autocomplete="off" />
<label>Username</label>
<input type="text" name="T3" autocomplete="off" />
<label>Password</label>
<input type="password" name="T4" autocomplete="off"/>

<div class="errorMsg"><?php echo $errorMsgReg; ?></div>

<input type="submit" class="button" name="signupSubmit" value="Signup">
</form>
</div></center>

INSCRIPTION :

<?php
$bdd=new PDO ('mysql:host=localhost;dbname=mydb','root','');
$a=$_POST['T1'];
$b=$_POST['T2'];
$c=$_POST['T3'];
$d=$_POST['T4'];

$req="select * from users where email='$b'";
$r = $bdd -> query($req);
$res= $r -> fetch();

if($res !=0)
   {
   echo "User déjà inscrit!!!";
   }
   else
   {
        $stmt = $bdd->prepare("INSERT INTO users ( name, email, username, password) VALUES (:name, :email, :username, :password)");
		$stmt->bindParam(':name', $a);
		$stmt->bindParam(':email', $b);
		$stmt->bindParam(':username', $c);
		$stmt->bindParam(':password', $d);
		$stmt->execute();
        echo "Confirmation de l'inscription!!";
   }

?>

LOGIN :

<?php
session_start();
?>
<?php
if( isset($_SESSION['ERRMSG_ARR']) && is_array($_SESSION['ERRMSG_ARR']) && count($_SESSION['ERRMSG_ARR']) >0 ) {
	echo '<ul style="padding:0; color:red;">';
	foreach($_SESSION['ERRMSG_ARR'] as $msg) {
		echo '<li>',$msg,'</li>'; 
	}
	echo '</ul>';
	unset($_SESSION['ERRMSG_ARR']);
}
?>

<link rel="stylesheet" href="style.css">
<center>
<div id="login">
<h3>Login</h3>
<form method="post" action="conn.php" name="login">
<label>Username or Email</label>
<input type="text" name="T1" autocomplete="off" />
<label>Password</label>
<input type="password" name="T2" autocomplete="off"/>
<input type="submit" class="button" name="loginSubmit" value="Login">
</form>
</div></center>

CONN.PHP qui permet de verifier l'utilisateur

<?php
session_start();
$errmsg_arr = array();
$errflag = false;
// configuration
$dbhost 	= "localhost";
$dbname		= "mydb";
$dbuser		= "root";
$dbpass		= "";

// database connection
$conn = new PDO("mysql:host=$dbhost;dbname=$dbname",$dbuser,$dbpass);

// new data

$user = $_POST['T1'];
$password = $_POST['T2'];

if($user == '') {
	$errmsg_arr[] = 'You must enter your Username';
	$errflag = true;
}
if($password == '') {
	$errmsg_arr[] = 'You must enter your Password';
	$errflag = true;
}

// query
$result = $conn->prepare("SELECT * FROM users WHERE username= :hjhjhjh AND password= :asas ");
$result->bindParam(':hjhjhjh', $user);
$result->bindParam(':asas', $password);
$result->execute();
$rows = $result->fetch(PDO::FETCH_NUM);

/*$r = $conn->prepare("SELECT * FROM users WHERE commentaire= :hh ");
$result->bindParam(':hjhjhjh', $user);
$result->execute();*/
if($rows > 0 ) {
header("location: home.php");
}
else{
	$errmsg_arr[] = 'Username and Password are not found';
	$errflag = true;
}
//if (("select * from users where type='admin'")){ header("location: h.php"); }
if($errflag) {
	$_SESSION['ERRMSG_ARR'] = $errmsg_arr;
	session_write_close();
	header("location: login.php");
	exit();
}

?>

merci d'avance