This could be a problem with the charger jack but is most likely caused by the tablets battery. First verify that your charger is functioning properly. Then be sure to let the device charge for longer than 30 minutes. If the device still shuts off, then replacing the battery may be required.

This is probably an issue with your WiFi module. First be sure that your network settings are set to detect new networks. Otherwise try turning off and back on the wireless detection on your device. If this doesn't work you need to replace the module.

First be sure that the lenses view isn't obstructed by any foreign objects, i.e. fingerprints, dust, etc. Also be sure that the lighting is adequate. If this doesn't help you may need get inside the tablet. When you take it apart be sure that the camera's cable is plugged in all the way; otherwise, replace the camera.