My digifusion 150 recently got powered down by unplugging it at the wall to use the socket for the hover :-( When i plugged it back in and turned it one it did't get past 'hold' message on the display on the front, none of the buttons work and it just sits there in that frozn state..... I've tried leaving it powered down for a while but no change.
I had the 100 briefly and had issues, one of the things i was told to try by digi CS was to disconect the power cable for 20 minutes, then before connecting hold the two buttons on the end inwhilst you reconnect the power and hold them in for 10 seconds ones the standby button and the other wwas the up button i think.
You should then get a message about formatting ect