Empty and black images and videos after rendering

Hi,

I was wondering what would cause that all the rendering/post-processing I do ends up with a bunch of black images or videos. I have version v2.73.
Interestingly, there is one of my blender files that renders nicely. Others do zilch. They did, but suddenly stopping, hinting I did something wrong (probably during my ventures of yesterday about another annoyance…).
I upload both cases because I can’t see what kind of blunder I’ve made.

QPS Logo Neons.blend (2.33 MB)
Graph DFB Scanner.blend (1.51 MB)

I hope a white knight saves me from another 6 hours of debugging.

Regards.

In the Render / Post Processing panel disable ‘Sequencer’ or delete the clips you’ve added to the video sequencer (that .png does not exist in the blend file supplied)
Also make sure you have lights in the scene you want to render


I know about the importance of luminosity; it was the first issue ever when I started Blender. In the one of the screenshot, the brand name is self-illuminating.
Indeed, I recall I had problems with the post-processing video montage feature of blender.

Anyways, I wonder if the problem avers to be the same in this following one: it is the one I desesperately need as final rendering, but the very first images (of seconds of the video) are pitch black.

https://mega.co.nz/#fm/8dl10KaT

I uploaded it there because there is a size file threshold (?).