Or try leaving the charger plugged in for 24 hours without checking the phone. then check it, with the charger still plugged in. If it works, unplug the charger from the phone and see if it stays on. If it does, use it until the phone tells you to charge it, turn it off and fully charge it. go through 3 cycles like that - full charge, use until the phone tells you to charge it. (If, during this period, you can't get to a charger when the phone tells you to charge it, turn the phone off.)
If it doesn't come back to life, you'll probably need a new battery, and that will require a trip to the shop if there's no warranty with the phone. HTC can do it, but a local shop can probably do it while you wait if they have a battery in stock. It takes about 15 minutes if the technician is methodical and slow.
03-23-2015 12:21 AM