A year or so ago, I bought an old Nexus 7 that was very slightly used (I took it off my girlfriend's hands). Everything worked fine, but I barely ever used it.
Two days ago I broke it back out. I charged the battery to full but never ran anything. The next day, I opened it up again and noticed that there was an update - 5.1.1. Not researching beforehand, I went ahead and tapped the notification, and then the problems started flooding in.
First, the tablet became locked in the loading animation after the Google logo. I let it do this overnight just in case, and it was still stuck in the morning. So I held the power button and volume button until it turned off and tried to reboot it.
At this point, it booted to a 'No command' screen. I did a factory reset from here, and rebooted. Now the tablet became stuck in a reboot loop of the Google logo.
After some research, I flashed it back to version 4.4. Everything worked fine with the fastboot and everything was working great. I ran a few updates from the tablet and got to version 4.4.4. Again, it loaded fine.
I tapped the envelope icon in the top-left corner to view my e-mails. As I was reading the first one, the screen froze. I let it sit for a few minutes and it was still frozen. So again, I powered off by using the power and volume button. My battery was around 30% at this point.
Now the tablet shows absolutely no signs of life. I have tried holding the buttons with all of the combinations that are online, I have tried doing combinations of buttons while plugging/unplugging the charger. I have tried using a regular micro-usb charger as well as a 2A charger. I have tried reseating the battery. NOTHING has worked. The tablet shows NO signs of life - no flashing, blanks, anything at all.
What else can I possibly do?