HTC One M7 :: Why Won't Phone Come Back On

I have a HTC One M7 and it was working fine lately, all of yesterday and this afternoon then i tried to hook it up to an AUX cord in the car and it was still working then when i too it off and laid it down i tried to turn on the screen and it would't come on at all but where the speakers are located as well as where the blinking light shows for notifications on the phone is blinking green like i have notifications and i know i do but i cant turn it on i tried holding down the power button nothing happens, i tried putting it on the charger but it wont charge the green light just keeps blinking. Last time my phone cut off it was because the battery was drained so i charged it and it worked perfectly fine but this time i dont know whats wrong because my battery was atleast on 60-70%