Why can't I view my pictures?

I have a Sony Cyber-Shot DSC-W650 and I used to be able to view all my pictures but now, every time I press the gallery button the screen turns black and freezes preventing me from using the power button to turn it off I’ll have to take the battery out and put it back in.

Also, when I go to take a picture, the camera will switch modes by itself. It’ll switch back and forth from camera, to panorama, to “movie mode” in a matter of seconds