What 's wrong for opening my new page? - php

Question

I tried to create a login page in PHP. I have a problem with opening the new page when the username and password are correct.
All the pages are in the same directory, which is Inventory.
Here is the code:
<?
$serverName ="localhost";
$dbname="inventory";
$conn = mysql_connect($serverName,"root","");
if(!$conn) die("Connection error". mysql_connect_error());
else echo "connected successfully";
if(isset($_POST['login'])){
if(empty($_POST['username']) || empty($_POST['password']))
echo "<script>
alert('يجب إدخال إسم المستخدم و كلمة السر';);
</script>";
else
{
$username = $_POST['username'];
$password = $_POST['password'];
$username = stripslashes($username);
$password = stripslashes($password);
$username = mysql_real_escape_string($username);
$password = mysql_real_escape_string($password);
$db = mysql_select_db($dbname,$conn) or die("database connection error" . mysql_error());
$query = mysql_query("select * from users where username = '$username' AND password = '$password'", $conn);
$name = mysql_query("select name from users where username = '$username' AND password = '$password'", $conn);
$rows = mysql_num_rows($query);
if($rows == 1)
{
//echo $username.'<br>';
//echo $password.'<br>';
//echo '<br>'. "correct user name and password";
$_SESSION['name'] = $name;
header("location: C:\xampp\htdocs\inventory\menu.php");
//echo "<script> window.open('C:/xampp/htdocs/inventory/menu.php','_self'); </script>";
}
else
{
//echo '<br>'. "incorrect user name and password";
echo "<script>
alert('اسم المستخدم أو كلمة السر غير صحيحة');
</script>
";}}}
mysql_close($conn);
?>
Any suggestions about what might be wrong?