Class 'CI_Config' not found

[eluser]Unknown[/eluser]
I tried installing a codeigniter project in my home system. I am using XAMPP. I was getting some depreceated errors. But I turned off error reporting.So it went off. But now I am getting an error "Class 'CI_Config' not found in C:\xampp\htdocs\myproject\system\codeigniter\Common.php on line 128. Can someone help me to fix the issue?