Had any joy with any of the suggestions in the other treads? some people have had to wait a very long time for it to spring back to life
What i detailed is what worked for me, might not be the same issue. I was tempted not to root and flash after this happened the last time. luckily i have next day swap out as a business customer.
Connecting to pc
Holding down the volume down and power button for 30 seconds
then try the adb devices command again please