My playback, Menu, and Delete (Green Mode) Buttons have just stopped working for no reason, whatsoever. When I press them, nothing happens at all and I don't know why. It has normal wear and tear as a point and shoot but this just happened for no reason. I was playing with some of the filters, turned off the camera, set it on my desk, came back an hour later - and none of the buttons are working at all. It's been three days and it's still not working. What do I do?