You know Gary, I've had lots of trouble with the GoPro3.
One thing I found is that when I empty the recorder via computer (deleting files on sd card) it will record for 15-20 seconds then shut off on its own.
I found through a search that one has to delete the files (reformat card) by way of recorder (sup'm to keep in mind). A couple of times it would not go on either. These things are so sensitive to everything.
It sucks having to update this update that .....I though I was just getting a recorder that "worked".