Hey,
Like many owners of this unit, I had the thing freeze on me every time I went to use it.
My fix up to this point was to just hit the reset button on the faceplate before putting it in.
But the other day I dropped my unit on the pavement, REALLY hard, bounced it good off its corner.
Resulted in a cracked outer shell and a big scuff on one of the corners.
I went to use it again, worked fine, just needed the reset like always. Then after work I put it in my car again for the drive home, and no display! Music played fine, but no display at all. Reset did nothing. I was like awww damn.
When I got home, I opened the battery cover on it, disconnected and took it out, and put it back in. To my surprise it turned on again! I put the faceplate back in my car, and it works! The added bonus is it hasnt needed a reset so far, and its been a few days 
Obviously I dont recommend using the pavement to fix the unit, but maybe try taking out the battery and putting it back in....