I went through your same problem then found this free program. It works flawlessly. Virus free and updates as needed.My Windows media player installed on my desktop does not recognize the MP4 file extension. I tried finding the CODEC online but all I found were files full of spyware and virus's? Any ideas of a clean easy to get source?
@ianwood , THANKS!Could be the second one wasn't closed properly. Put the card back in the cam and turn it on. It should repair it.
You didn't press stop recording before you turned the battery off