wp-admin shows blank page, how to fix it?

Question

I am working with WordPress 3.5.8. Yesterday I made some changes into it to a friend. I don\'t know what happened, but after some time when I try to log in at wp-admin side and

Answer 1

Try turning on WP Debug. If this is happening due to a PHP error (which I bet that it is), you will be able to see what's going on and fix the error.