Kindle 4 NT Frozen at Screensaver

Hi Guys, my kindle 4 non touch is currently stuck at the screensaver/ad screen, and is unresponsive. I've tried pressing the power button for 40 seconds to do a reset but nothing happens. I've plugged it into my mac, and the orange LED lights up, but my mac doesn't detect it.

Is there any way to solve this problem?

Thank you in advance.