My controller died during an update and would not turn on no matter what I did. I fixed this issue by using a known good USB -> Micro USB cable from my phone charger, and fresh batteries in the controller (do NOT assume your cable is okay - try another one if you have it). Turn off the Xbox One and unplug it for a minute or two. In the meantime, plug in the controller using the USB to the side port (probably any port will do, but that's the one I used). Plug the console back in and turn it on using the button on the console, not the controller. After a minute, the light on my non-functioning controller lit up and all was good to go. Good luck, hope it works for you too! If you continue having issues turning on your Xbox One Wireless Controller, check out this Xbox One Wireless Controller Won't Turn On Problem Page.