Ok, so after your recordset is filtered correctly you will check it to determine that a record has been returned. Here is an example of what that code would look like:
<?php if ($totalRows_your_RS > 0) { // if recordset not empty
if(!session_id()) session_start();
$_SESSION['your var'] = 1
header("Location: your_email_password_page.php");
?>
You would of course need to update this code for the name of your recordset, session variable and email password page. The session variable can have any name that you want, you just need to ensure that you are referencing it the same when you set it and test for it on the email password page.