Help to load the page

[eluser]Unknown[/eluser]
I am developing a website for my company and I am struck in making the app run. I am able to see only the home page when I type in the URL http://localhost/codeigniter

For instance, when I type in http://localhost/CodeIgniter/admin/login/ the page is not loading up and displays an error message.

"Not Found

The requested URL /CodeIgniter/admin/login/ was not found on this server."

Please find the directory structure of my app below:
C:\wamp\www\CodeIgniter\system\application\modules\admin
Controllers
Views

I am reading the files from a separate folder called as modules and modified the path accordingly in the libraries folder.

The following is the base site URL that I have set:
$config['base_url'] = ((isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == "on") ? "https" : "http");
$config['base_url'] .= "://".$_SERVER['HTTP_HOST'];
$config['base_url'] .= str_replace(basename($_SERVER['SCRIPT_NAME']),"",$_SERVER['SCRIPT_NAME']);

Please help me out in this regard. I have the entire code ready but the links are not showing up appropriately!

Thanks,
Pavan