Using VSE. Rendered video and now nothing is showing up. I've been using the VSE for awhile now and have yet to encounter this problem. 

I finished editing my video and clicked render animation. Everything seemed to be going fine. After the video finished rendering I went back through to watch the rendered video and it was just a black screen with no sound. Image overlays I had added to the video would still show up at the appropriate times, but no video or sound. 

I tried reloading the file and restarting Blender, but neither of these things works. Can anyone give me any advice? It took me 3 hours to finish editing this video and now it's just gone.
In order for overlays to actually overlay existing video, you need to add an effects strip to tell Blender how to mix it. Generally I use the alpha over strip, but there are other options like alpha under, add, subtract, etc). 

Otherwise, the VSE takes the top most strip and uses that. Without the effect strip all you'll see is the overlay and nothing but black. 

Now if you had some B-roll or stock footage or images that will cover the whole screen, then you wont need a effect strip. Just make sure it's in a higher channel than any other video channel.