From what I gather, the LG models after the G3 have had an issue with the capacitors not being able to sustain a charge after some months of use. This may be a result in letting the phone die over and over again. Once it boot loops once, or won't power on, give up on it. Take it to LG within the 1st year of purchase (if applicable). If you bought it more than a year ago without insurance, you're out of luck.