At this point, you need to try a factory reset. I know in your first post you you tried "resetting the device", but, was this a factory reset? Or simply pressing the pinhole reset button? The latter will restart the device if it hangs, but doesn't do anything else.
The factory reset for an Aura HD is:
- Charge the device for at least an hour.
- Hold the power button down for about 20 seconds to force it to power off.
- Hold the light button down and turn the device on.
- Release the light button when the screen starts to change.
I generally need to do this a couple of times as I either let the light button up to early, or maybe didn't hold it properly. But, if it doesn't work the first time, try again by wait longer at each step.
If this doesn't fix things, it is probably hardware. But, the only hardware you can change is the internal SD card. You can open the device and replace this, but you will need a disc image to replace this. This is available for asking. But taking it out and checking it will tell you if there is a problem. Also, reseat it to make sure it hasn't shaken loose.
The only other thing I can think of is damage to the screen. That doesn't sound likely, but it could be. If this is the case, it might be booting OK, but the screen can't be updated. Something to try is wait for however long it would normally take to start and try to turn the light on or off.