Your camera's battery could almost be out. You'll need to charge it if that's the case! Also, the screen could be broken. You may try replacing the LCD screen.
Your camera's battery could be too low to produce a flash. Make sure that it's fully charged! You could also have the flash settings set to "off" or "auto." Go to settings on your camera, and make sure that the flash is put on "on." If neither of those work, you may need to replace the flash because it's broken.