if this has happened to you with multiple electronics, perhaps the problem is that you are storing your electronics in a hot environment or by something very magnetic... or as Over mentioned, perhaps in the sun. i've only had electronics turn black when they've been in the sun.
Originally Posted by tompe
I read it as that they did not fix the problem since it was intermittent and just sent the Cybook back that they thought was working. That has happened for me with other electronic products.