As my dad always said never over look the obvious, that being said do you have the correct battery? These camera batteries all look alike and it can be easy to pick up the wrong one. Now assuming that you have the right battery and it still doesn't work then that means its the camera and not the battery. Make sure that the battery slot is clear of debris on both the top and bottom. Something may be blocking the contacts. Another possibility is the door that holds the battery down could bad or worn away. See out replacement guides on how to replace that. The other issue could be the circuit board. Something could have shorted (something with power gets connected to something that should NOT have power, resulting in something getting fried. You can confirm this to see if there are black marks on the board.) or a component went bad. If either of these are the case then you might as well get a new camera, unless you can solder and find the component that has gone bad, which is rather difficult.