Software failure- now phone won't turn on at all

[Android Central Question]

In March/April my M9's software was failing and I got an M10 instead. I had brought it to Sprint and they told me the software was corrupted, making my text messages come in literally days later, operating system not working right, couldn't make any phone calls without having something popping up on the screen and ending it, couldn't receive calls, etc...
Instead of resetting and losing everything, I got a new phone. I had the "what if" thought of "if I reset my phone and it doesn't fix it, I lost everything (without having a spare phone to transfer everything to, and still have a broken phone."
I transferred everything to my M10 over a few days. Recently, I went through my drawer of old phones and I was turning them all on to see what I have on there. I have a picture that didn't transfer over from a text message that I want to get, and now the phone won't turn on at all.

I charge it and the battery does charge up (because it feels hot like it used to do when I used the phone.) I try VOL+ and power, power, VOL-, VOL- and power, and nothing. What can I do? I want to at least get the phone to power on. Could I take it to Sprint and see what they can do?

 

[belodion]

A hot battery is not good. Are you sure it's the battery that's hot? If so, it may be worth replacing. Whether that would make the phone work is a different matter.

 

[Webby702]

The back of the phone is warm around the camera and along the back, currently. I've had it plugged in since I made this post. For what it's worth, my battery never went below 60% when I used the phone, aside from one time I had it in developer mode and it went to 10%, and when I got the phone it was at like 38%. I've always been v conscious and generous with my battery levels.

 

[Rukbat]

If it doesn't turn on after the battery gets above 50%. the only fixes will wipe all your data - including the picture you want.

In the future, back the phone up completely every week, at least. (Then check the backup - if it's good you can delete the last one.)