Help!System restart

Hello, after having some problems with the free space in my nook simple touch, I decided to erase the free space. I used my mac's disc utility and erased it. Something went wrong, I think I erased the drivers, and now the only thing it does is giving me the message:
"your nook encountered a problem that requires a system restart. If this problem persists, please contact customer service".
Unfortunately I'm in Italy and can't contact customer service. What should I do?
Thank you