Casio Pocket Viewer PV-S400Plus not working

When batteries are to be replace you must move the switch on the back cover to "replace batteries". After you replace the batteries, you must move the switch back to "normal operation". The unit will then want you to touch the dots in the cross hairs and then ask you to adjust contrast. Try replacing the batteries again with a fresh pair. If this does not work, open the cover with the switch in the "replace batteries" position and use your stylus to press the "P" button underneath the battery cover and try again. If this fails, try resetting the unit.