Chances are the card is not empty. Most cameras will only show images or videos if they are located in a folder that matches the name the camera produces when it creates a folder to save it’s own images and videos. For example a Nikon camera will most likely place and retrieve images only from a folder called “NIKON.” The GoPro videos are located in a folder called “GOPRO” which is within a primary folder called “DCIM.” For best results, copy the files to your computer before trying to view them. If you don’t have an SD card reader other than your camera, you can purchase one (usually under $10) from an office supply or consumer electronics store. Just make sure the reader you are purchasing can read an “SDHC” card.