This has probably been asked and answered elsewhere, but I can't find it, so....
I designed a simple animated logo in Blender, with a spinning earth between two light-emitting text objects, with two point lamps for extra light. I rendered and saved the animation, and then used a gif conversion utility to save it as a gif. That all worked fine, but ...
... I decided I wasn't satisfied with the lighting. So I did Save As to start a new file, deleted the two point lamps from my original file, then added two Sun lamps (a Sun emitting a golden color from the left, a Moon emitting a pale blue from the right) and two dim Hemi lamps for high- and low-fill.
But when I Render I still get my original lighting. Similarly, if I Render Animation, I still get the original lighting.
How do I refresh the render process so I can see my new lighting?
Here is the Blender file:
UPDATE: Simply, it's not performing new renders. I deleted all of the original render frames, then clicked Render ... and I get a blank screen, because render image it had been displaying is no longer there.
UPDATE2: I went back and reopened the original file, from which I did a Save-As to create this new file ... and the original will not perform a new render either.
If I click the Render button, I get a blank screen, because the previous render (that it had been displaying) has been deleted.
Again, this is not about what I see in my 3D View. I see my lighting changes there. But I can't render a new image, or a new animation, at all.
UPDATE3: The solution was, per the answer below, to turn off Sequencing and Compositing in Properties > Render > Post Processing.
The relighted animation starts with this frame:
In the 180th frame, the earth has almost completed one rotation:
The lighting looks as I'd hoped: warm sunlight from direct left and cool moonlight from direct right, with dim neutral lights along the centerline to mute what would otherwise be a deep shadow at the sunset-moonrise horizon.
In clock terms, it's 12:00 noon on the left rim of the earth, and 12:00 midnight on the right rim. In terms of physics, my moonlight is far too bright; it's 1/2 the intensity of the sunlight, whereas in reality the ratio is about 1:400,000. But with the cooler color, it gives the effect I wanted.