ปัญหา header("location:Login.php"); ทำงานกับ switch($_POST['page']) ต้องทำยังไงอ่ะครับ

<?
$Act=$_GET['Act'];
$Username=$_POST['Username'];
$Password=$_POST['Surname'];
switch($Act){
    case 'Login' :  $Select=mysql_query("SELECT * Form member WHERE Username='".$Username."' AND Password='".$Password."'") or die (mysql_error());
                           $Num_Row=mysql_num_rows($Select);
                           if($Num_Row==1){
                                   echo "ok";
                          }else{
                                  header("location:index.php");
                          }
     break;
}
?>
<form act="?Act=Login" method="POST">
<input type="text" name="Username" value="">
<input type="Password" name="Password" value="">
<input type="submit">
</form>
</form>