Sort out Content not loading in Web Page

Hi there, I need help with trouble shooting an issue I have.

Issue:

1. The web page loads with a web page and some of the links work but not all
2. The nice and thrilly content is not loading.

Environment:

1. The web site is on a Centos server
2. Httpd services are running
3. MySQL services are runing
4. Permission on the the www directory has not changed.

Recent Changes:

1. Individual with Admin rights had tried to upload an image. They have done this before with no isses.

How do I trouble shoot if there is an issue with:

1. expressionengine/engineroom not getting correct information for MySQL?
2. is there an issue with code igniter?
3. Can i reverse changes within the engineroom
4. Is there an issue with Modules not being loaded?

help is needed,

Thank You,

troy