Can I get my phone to turn back on? Please, please help!!

[AC Question]

My HTC One M8 has had a 'System Update Available' message for the past few weeks, however every time I try to launch the update, I get a message saying it has failed because a certain file is missing. Since then, my phone has been acting strange (slower, less responsive, crashing regularly). Today when someone called me, I got a message box saying something like the android system has failed and although the signal/wifi bars were still moving on the screen, I couldn't press the power or home buttons etc. My phone then turned itself off - I turned it back on without an issue and decided to re-try the system update in the hope it would finally work and my phone would stop acting crazy. My phone downloaded the update and took me to a screen with a list of file names and the option to unzip them. I selected the unzip option hoping that it would work and it began to unzip the files but at around 15% through the process, my phone just turned off. I tried the different button combinations etc but still nothing is happening and even when plugged into the charger, there's no charging light on. About an hour later, my phone booted to a "***Security Warning***" page with options to reboot, fast reboot, shut down etc (I can't remember the other two options).. I selected reboot and the screen went black again but nothing happened. About another hour later, the same "***Security Warning***" page popped up randomly, so I decided to select the fast reboot option in the hope that might encourage some response, but still nothing.

I'm so desperate to try and find a solution here. I use my phone almost constantly for work and university and I don't have a computer so without my phone, I'm screwed. I'm barely scraping by financially also, so if I can't find a way to fix the phone myself, I'm also screwed. I'd really, really appreciate any help or suggestions!!!

 

[Rukbat]

The easiest way to start fixing that is to reflash the ROM, but without a computer you can't do that. Taking it to a repair shop would be next but you can't afford that. You're going to have to find someone with a computer who knows HTCs to fix it for you for free.

 

[B. Diddy]

Welcome to Android Central! Try wiping the cache partition from the Recovery Menu: https://support.t-mobile.com/docs/DOC-10672