"404 Page Not Found" error, do I have a CodeIgniter routing problem?

I am using CI for my web-site. While programming CMS for the same I faced no problem but when I am programming the same for user-end I am getting error as:

404 Page Not Found

The page you requested was not found.

What am I doing wrong?

In Controller(model.phpl):

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
class Model extends CI_Controller
{
    function __construct()
    {
            parent::__construct();
            $this->load->model('user_model');
            $this->load->model('common'); 
            $this->load->model('home_model');
            $this->load->model('page_model');
    }

    function _remap($method , $params = array())
    {
        $this->menu = $this->common->createMenuArr();
        $this->index();
    }
    function index()
    {
        $data['sliderArr'] = $this->user_model->sliders();
        $this->load->view('index', $data);
    }         
}

In Model(user_model.php):

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
class User_model extends CI_Model
{
    function __construct()
    {
        parent::__construct();
        //$this->load->database(); 
    }

    function sliders()
    {
        $query = $this->db->query("SELECT slider FROM tbl_sliders ORDER BY slider_id DESC")->result_array();
        return $query;
    }          
}

and finally in view(index.php):

<div id="slideContainer">
    <div id="slideShim">
        <?php
        if (!empty($sliderArr)) {
            foreach ($sliderArr as $slider) { ?>
                <a href="#"><img src="<?php echo base_url();?>images/sliders/<?php echo $slider['slider'];?>"</a>
            <?php }
        }
        ?>
    </div>
</div>

Go to Application -> Config -> Routes.

And Set $route['default_controller'] = "index"; //whatever your controller name is on which you want your application to route by default

Hope this helps.