If he went to the Nookdevs website to read the directions on how to root, then the OP knows that he could void his warranty by rooting. Period. It's listed FIRST on the Nookdevs site.
But Hanscraft, I promise you, you didn't root your device. I also had a problem the first time after I tried rooting, and I had to do a factory reset of the device--it turned out to be harder than actually rooting!
Just follow the directions here and you'll be fine. It's kind of nuisance when you're trying to power up the NC eight different times.
You have to hold the button down, wait for it to power off, and then restart it. It is very important that you wait until you're seeing the "Touch the Future of Reading" appear on the screen, and then immediately HOLD DOWN THE POWER BUTTON until it shuts off again.
The mistake I kept making was that I would merely push the power button, but in order to power it off, you must make sure that you're holding it down while it's booting up.
Repeat the process 8 times and you should be good. If it doesn't work the first time, keep trying.