|It's possible a bad battery could show fully charged but not work. So you might consider trying a new battery. Or depending on how you determined it was fully charged, it might also be a problem with the charger. Make sure the charging connection is making good contact.|
If all that seems OK you can check that the battery is making good contact with the terminals in the camera but other than that it sounds like an internal failure. It might just be a fuse but that still would require opening it up. Probably only something a shop should do.