So that any responder does not repeat steps you have taken, what have you attempted to do to solve this issue?
- Turning on and off the camera sometimes will fix it.
- If you are in AF mode and the camera cannot get focus it will not fire the shutter.
- If it is in a low light area, reason the flash popped up, and the camera cannot find something to focus on it will not fire the shutter.
There are a number of things that can cause this, some nothing to do with an errant camera.