One thing springs to mind, just in case it hadn't occurred to you - can you try a different mains socket with the X7's power adapter please? I had a six way adapter where one of the sockets stopped working (wiring came off I assume).
If that doesn't help, please e-mail us (
[email protected] ), with a link to this thread -
http://www.droidboxforums.com/posts/1358 and your postcode and order details (order ID, account name/e-mail address used for the order). Please ask them to send you the dead device template.