Preview window is empty version 2.78 on Ubuntu 17.10 and in Win10

I am new to Blender. Installed 2.68 from the Ubuntu software center and have been working through Mikecal’s tutorials to learn how to use Blender in editing my videos. Decided to install 2.78 (just because), and in both OS’s I’m getting that checkboard overlay that in most every editing program indicates that there is nothing to display.

I’ve done searches on this forum and on the internet. Found one specific instance of someone asking about the exact same problem. The reply was to simply reload the file. Well, have tried that and it does not work.

I know this must be something simple, and would appreciate advice as to what I am doing wrong.

This is my first post on this forum.

Thanks.

Caruso

So, I have discovered that the problem with my preview screen (sorry, don’t know what you actually call this), is related to the fact that I created this particular video in version 2.68. I am not certain why that matters, but if I start a new project in 2.78, it works normally.<br><br>The project in question is not golden. I have all the original footage and put it together for practice and training, but I would still like to know how to fix the problem I am certain (more than ever) that it must be something really simple.<br><br>Sorry to post a new thread as a follow-up to the first, but, because I am new to the forum, the original post is not showing up yet.<br><br>Thanks for any advice.<br><br>Caruso