Trouble with basic navigation.

[eluser]Unknown[/eluser]
Your form action should be "index.php/home/login". You can also use the CI built in function to open form:
form_open(). You will not need to add index.php if you use form_open() method.
<?php
$this->load->helper('form'); //must load the form_helper before use
echo form_open('welcome/login'); //will produce<form acti method="post" accept-charset="utf-8">

//to close form
form_close();
//more about form helper here
?>