I recently upgraded my Dell Venue 8 Pro to the latest version of Windows 10, and that worked fine. Then the Dell update software prompted me to do a device update (if I recall correctly, it was a chipset driver update). That update started to be applied, and then the screen went black (but the backlight was still on) and the tablet became unresponsive. I let it set for several hours (while still plugged in to the charger), then tried to turn it off (holding power key for 10 seconds, power plus volume key, etc.). Nothing worked. I then unplugged the charger and let it sit for a couple of days. Eventually the yellow (orange?) led came on (apparently indicating low battery), and finally the backlight eventually turned off. I then tried to charge it (white LED came on for a while), and then a few hours later I tried to turn it on. No response. Holding power key for 10 or more seconds and then trying to power on still has no response.
So it looks like that Dell prompted chipset driver (the only update suggested) has "bricked" this tablet. What else can I try to get it going again?
Turns out that after sitting for another day my Venue 8 Pro did finally boot, so this problem is now solved (at least for now). I do have a question about that driver update that caused this problem, but I will post that in a new thread with an appropriate subject.