Black screen ASUS Transformer TF301, what can I do to recover?

My Transformer TF301 is stuck at a black screen, well sort of a backlit black screen. I have tried Volume Down-Power (for 10, 20, and 30 seconds) no joy. VolumeUp-Power, no joy. Finally found something thin enough (staple in the end) to push the hardware reset button. No joy. Holding power is not shutting it off either. My son (six years old) is the only real user, and I cannot imagine he installed/rooted it. I see no visual sign that he damaged it. It is in a case as well, which should mitigate any physical damage he might cause. If I hold power button it goes black, but any other press and you get a backlit black screen. Nothing seems to budge it. What are my options to recover?