Create lightbox effect for images and videos using Jquery or PHP for existing site. Do not allow ''Back'' click

PLEASE!!!! READ ALL OF THE TITLE!! PLEASE!!!! READ THE INSTRUCTIONS!!! PLEASE!!!! ONLY BID IF YOU KNOW HOW TO CODE!!! PHP and Jquery Cake Framework is already set up. The site functions properly. 1. Create a "lightbox" effect whenever a images, video, files, or pages icons are clicked at the top of my quiz site. Right now they open in new pages. I want to screen to take on a lightbox effect so that the users do not leave the exam. Sample: [login to view URL] 2. When user currently take exams, they are allow to click "back" I do not want them to be able to do this. I would like this all done without messing up the functionality of the site. The site is active, but I currently do not have users. I want some little things done first. It's on a dedicated server. I will provide user info. Right now, the admin or user can create a quiz, they can select to add a file or upload an image, after they do the file or image the chose appears at the top of the quiz in an "Image icon" When they click on the image icon, the file that the creator of the quiz uploaded is accessed. I want to make sure that the screen dims and this effect takes place.