Codeigniter vhost LAMP configuration troubleshoot

Ruing LAMP on UBUNTU 14LTS on virtualbox from win7 I found some hiccups.

I'm having trouble displaying my code igniter project in my machine. I have a followed some guides including this one: tut 1 and tut 2

I can make the current configuration show a single HTML page, called example.com but it caot show a complete code igniter project, I get this error when ruing it through the localhost:

NOT FOUND The requested URL /alpa_blog/en was not found on this server.

The project I'm working on is very big so bitnami is a bitslow so I'm plaing to change to LAMP that is why I wanted to try and see a little blog on my localhost. I have not used the LAMP on apache 2.4+ so I'm a little confuse about how to edit some files on vhost and tie them to the config.php inside code igniter.

I've tried a lot of different combination things but no success yet. Now I have my files @:

/etc/apache2/sites-available/alpa_blog.com.conf
/etc/apache2/sites-enabled/alpa_blog.com.conf

Looking like:

<VirtualHost *:80>
    ServerName alpa_blog.com
    ServerAlias www.alpa_blog.com
    DocumentRoot /var/www/html/alpa_blog.com/application

    ErrorLog ${APACHE_LOG_DIR}/error.log
    CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

And @ /etc/apache2/sites-available/000-default.conf

looks like:

<VirtualHost *:80>
        ServerAdmin webmaster@localhost
        DocumentRoot /var/www/html/
        ErrorLog ${APACHE_LOG_DIR}/error.log
        CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

<Directory /var/www/html>
        Options Indexes FollowSymLinks MultiViews
        AllowOverride All
</Directory>

Plus my file alpa_blog.com/config/config.php code igniter's folder looks like:

$config['base_url'] = 'alpa_blog.com';

My etc/hosts folder looks like:

127.0.0.1 localhost 127.0.1.1 alpalamp-VirtualBox 127.0.1.1 example.com localhost 127.0.1.1 alpa_blog.com localhost

My var/www/html folder looks like:

alpa_blog.com ci example.com index.html phpinfo.php

Any pointers are much appreciated. Sorry for the your supposed to know that question, but it's driving me nuts.