Untitled

<?php
include('include/config.php');
echo '<html><head><title>Prodigy Booter</title></head><body>';

if (isset($_POST['submit'])) {
    if (!(isset($_POST['Username']) && isset($_POST['Password']))) { die('Please fill in a Username and Password.'); }
    $Username = mysql_real_escape_string(strip_tags($_POST['Username']));
    $Password = md5(mysql_real_escape_string(strip_tags($_POST['Password'])));

    $sql = "SELECT * FROM users WHERE username='" .$Username. "' AND Password='" .$Password. "'";
    $query = mysql_query($sql);
    if (mysql_num_rows($query) > 0) {
        $_SESSION['login'] = $Username;
        echo "Successfully logged in.";
    }
    else {
        echo "Username or password is either wrong or doesn't exist.";
    }
}
else {
    ?>
    <form action='login.php' method='POST'>
    Username: <input type='text' name='Username' /><br />
    Password: <input type='password' name='Password' /><br />
    <input type='submit' name='submit' value='Login' />
    </form>
    <?php
}

echo '</body></html>';
?>