This exact thing happened to my wife's M yesterday as well. All I did to get it back up and running was take it out to the car (as we were out to lunch) and plug it into the charger and it rebooted all on it's own. Never touched any buttons or anything. Strange why that happened though. She was just trying to open up Song Pop and it froze and she tried to power it off and reboot and this happened.
I was the originator of this post several months ago. I have not had this problem again. This is one awesome phone with a lot of good capabilities. Just got the jellybean upgrade earlier this week. Very satisfied except for the first week hiccup.
My RAZR M did the same thing only it ran out of juice and refused to charge or reboot while plugged into the wall. I tried holding the buttons but no joy. I decided to try the car charger and it worked! It started taking the charge and after a minute or two it started right up. The wall charger didn't have enough punch to get the battery to accept the charge at such a low state.
Sorry for my English
need help to restart my phone
I wanted to root my phone but made a mistake somewhere.
now the phone is always off. when connected to the computer program RSD see him as QHSUSB_DLOAD
when pressed power button for starting nothing happens
when pressed power button and Volume Down nothing happens to