I was recording and video on my phone when the battery died, how can I recover the video file? I read the other questions I could find. This is completely different. My question is NOT about finding the file.

The file is on my phone. It is the correct size. It shows as an mp4 with the right icon on windows. It has an mp4 suffix. It's 22+MB so it's there. It will not play in MS Media Player or with VLC player. It doesn't show up on the phone itself in the gallery, but it's there when I connect the phone to my laptop.

I was recording the video, my battery died, the phone shut off while I was recording.

There are many programs on the internet that claim to fix video files, but I'm afraid to download any of them because I do not want to get a virus.

My phone is an HTC EVO 3D. My carrier is Sprint. My laptop is a Samsung running Windows 7. I recorded it regular mode not in 3D mode. 

How do I play this file? How do I fix it? What should I do? If there's a piece of software I should download to my laptop to fix it, what is a good reputable site where I won't get malware/virus?
I had the same promblem. A solution which worked for me was an app "MP4Fix", which you can get in google play for free. It repaired my video in a few sec and placed it in different folder (it kept corrupted video in the same place and also created new repaired one). 
I know this info might be too late for you but it might help some others.