HTC One M9 won't turn on My HTC One M9 is fully charged, but will not turn on. The red charging light is on, not blinking.

None of the buttons respond.

Many sites say to hold the Volume Down button, then press the Power button. That is not doing anything, even after holding them for a minute.

When plugged into a computer, the computer recognizes that there is a device plugged in.
Turns out that holding Volume Up and the Power button for about 15 seconds forced the phone to turn off.

Then, tapping the Power button turned it on, and it booted up with no problem and seems normal now.