Camera/screen works in playback but not in camera mode

Camera turns on and works fine in playback mode. But as soon as you press the shutter button, the power goes off leaving a blank screen. We went to the beach last fall -- could it be sand? However, the camera worked fine until just a few months ago. Wanted to open it up to see if I could see any sand, but don't have a screwdriver small enough to do the job. Any suggestions?? Need to get it fixed quick with the holidays coming up!