Need to create an e-learning menu

I have taken on a job that requires more knowledge than my basic HTML skills: I have been creating a set of multimedia DVDs for a local medical organization. It's just a basic HTML menu/web page with links to video content stored on the disc.

For the new project, they'd like it to be in an "e-learning" format, i.e., you can't view the second video until you've viewed the first, and so on.

I know that I can do this with a type of server-side validation, but since everything is on a DVD, that won't work. I'm sure I can do it with JavaScript and cookies, but that's beyond my basic knowledge.

The menu is just an unordered list. I just need a way to hide the subsequent list items until each previous item is viewed.

ANY help you can provide would be greatly appreciated!