nighthawk ac2100 Did a firmware update last night, router has 2 red lights on and now is dead

1. What actual router do you have? AC2100 is a speed

2. What firmware did you install? 

3. What 2 lights are red? 

If something was corrupted during the firmware update, you could try a factory reset first. 

Push and hold reset for 7-15 seconds while powered on. 

If that doesn't help, you can try recovering it with tftp or nmrpflash.
are you on windows? if so, follow this guide
https://kb.netgear.com/000059634/How-to-upload-firmware-to-a-NETGEAR-router-using-Windows-TFTP
just make sure you enable tftp
https://www.thewindowsclub.com/enable-tftp-windows-10

and here's a video walk through using a tftp client. Use the built in one for windows 10 though. the video is more of an example of how its done.
https://www.youtube.com/watch?v=R9DLrLQrpaw

and if that doesn't work, you can try using nmrpflash
https://github.com/jclehner/nmrpflash