You can try a manual factory reset.
Edit: Add step 0. Charge your Kobo for at least a couple of hours before trying to do a factory reset.
- Turn off your eReader by holding the power button for 20-30 seconds
- Press and hold the light button. Do not release it until step 5
- While holding the light button, slide the power button to the right to power on your Aura.
- Continue holding the light button until the power light blinks rapidly (discoing).
- Release the light button.
Good luck.
Out of a perhaps morbid curiosity, where did you obtain the KoboRoot files you were trying to use on your Aura?