Neglected iPhone Unresponsive
So I was out of town for a few weeks, and my iPhone (5S, for reference) was completely neglected during that time. No one dropped it, no one messed with it, no one even touched it. I got back, charged it up, and... nothing. The screen is black, and it's not responding to any combination of button presses. It's just... dead. I may as well have taken the battery out.
That's not a lot to go on, but there is something else odd. I also have a Chromebook. It was also untouched for weeks on end while I was out of state. When I got back, it gave me the "Chrome OS is missing or damaged" error, and I had to recover it, wiping my hard drive in the process.
The two devices were in the same place at the same time, so I can't help wondering if the iPhone might have a similar issue. (solar flares or something) And I can't find any information about recovering the OS except this -- http://www.imore.com/how-to-iphone-ipad-recovery-mode -- and I can't get that to work either. Is a missing or damaged OS even something that happens? Or is there some perfectly reasonable explanation for how my phone apparently broke itself?