When I switch my camera on it beeps four times then switches itself off.The battery is fully charged.It is a Pentax RZ18.

[Adam]

Have you used the camera a lot? If so, the battery could no longer be holing its charge properly. Another common thing that breaks is the lens motor. If the lens doesn't slide in and out smoothly, or not at all, this could be the case- and that would probably mean it's time to replace the camera.