this is dashboard.php

<?php
class Dashboard extends CI_Controller{

function index()
{
$done=$this->session->flashdata('userEmail');

if(!$done)
{
echo "not login";
$this->load->view('main/login_form');
}
else
{
echo "welcome to dashboard" ;
$this->session->keep_flashdata('userEmail');

}

echo "<br/>" ;


}


}


?>

and this login.php code::

 public function login()
	 {


	if(isset($_COOKIE['wathba']))
	{
	$this->session->set_flashdata('userEmail', $this->session->userdata('userEmail'));
	redirect('dashboard');

	}


	 $this->form_validation->set_rules('userEmail','email','trim|required|valid_email|callback_check_login');
	  $this->form_validation->set_rules('userPassword','password','trim|required|md5');


if($this->form_validation->run()==TRUE)
		{



	if($this->user_model->Login(array('userEmail'=>$this->input->post('userEmail'),'userPassword'=>$this->input->post('userPassword'))))
		{  redirect('main/login');


		}



	else
			{


$this->session->set_flashdata('userEmail', $this->input->post('userEmail'));
$check_box=$this->input->post('remember');
echo $check_box ;
if ($check_box=="remember me")
{
echo " checked" ;
$value=array('userpassword'=>$this->input->post('userPassword'),'userEmail'=>$this->input->post('userEmail'));
$value=serialize($value);
$cookie=array(
'name'=>'wathba',
'value'=>$value ,
'expire'=>'2410000', //in seconds
);
$this->input->set_cookie($cookie);

}

the problem is that i have cookies stord in my computer , and when login is redirect me automatically to
dashboard.php and give me the result of

echo "not login";
$this->load->view('main/login_form'

that is false , it must echo "dashboard"

how can i use instead of this sentence  $this->session->set_flashdata('userEmail', $this->session->userdata('userEmail'));

(how i can use data from cookies ?)