Answer to: Samsung galaxy J5 not turning on and not chargingWhat caused this problem? Did the phone fall down? Try check if the battery is in good health. It may just be the reason. Also check out this Dead phone Solution – How to Revive a dead phone article. It should help
Answer to: Mysterious setting reset and hotspot problemHello. First thing I will recommend is reseting the phone to factory default. Is any part of the phone broken? perhaps the part with the wifi network antenna. If this is the case, You will need the help of a technician. Get more help here DEVICETECK
Answer to: will not turn on or chargeI think your need a technician to fix this. I am a technician and I have lots of similar issue often. It could be that the USB charging port is bad and unable to charge your phone while the battery is completely dead. Try this. Get a healthy battery, insert it on the phone, turn it on and note the difference.