ReadyNas Duo RND2000-Trouble shooting inaccessibility

My ReadyNas is about 2 years old was running fine with one 1 TB disk and dont have redundant disk installed yet (My bad) . Suddenly it was inaccessible and the background task was active continuously for hours together. I followed the instructions to reset the device by pushing the reset button for 5 secs until the green light shows indicating the acknowledgment of the firmware upgrade command. I left it on with roaring sound for several hours for the upgrade. But nothing seems fixed. I cannot power off using poweroff button but only by removing the power plug.

I am hoping I have not lost any data. Any help in fixing this is greatly appreciated.

Thanks much