HTC One M7: Not working, battery dead?

[AC Question]

My phone was below 10% when i plugged it to charge. It was late so I went to sleep. Several hours later i woke up and saw the Green led that indicates that the battery is charged. I pressed the unlock button and nothing happen the screen was black. So i held it for longer and nothing happen i tried the vol down + power button nothing also happen i held it for at least 2 minutes. No response. When ever I leave the phone to charge it doesn't get warm. It stays ice cold. Is the phone disposable or any solutions? Thanks in advance!

 

[Rukbat]

No way to tell without opening the phone. It's going to have to go to a repair shop.