Many owners of the HTC One have experienced sudden problems of the phone turning off and not switching on back again. On plugging the HTC One to a charger, the phone does not respond, neither does the red color LED Light glows on the top left.
What do you do in this case?
Lets take a look at HTC One Not Charging or Turning On – Solution
If you find out that your device does not turn on, is unresponsive, or has a black screen use the following steps below:
Plug your HTC One into the wall charger that came with the box.
Note : Do not charge the device using a computer or laptop, because it does not provide enough power to ensure the battery will charge completely.
Charge the phone until the red LED glows solid. (This can take time, up to 20 minutes)
When the HTC One is on charge, press and hold the Power Button for 15 seconds. If the device still does not turn on then press and hold Power, Volume up and Volume down button for 1 – 5 minutes.
This process re-calibrates the battery, and allows you to power on the HTC One.