I bought a TF810C VivoTab a few months back and I was using it in a lecture today then after trying to rewake it after it went into sleep mode I would no longer get any response.
Sometimes when I hold the power button down for a while like you would when you're booting it it will vibrate but I wont get any further response from the device. The battery level on both the tablet and the keyboard dock were around 90% when I was last using it so it's not a matter of it having a dead battery.

Any ideas?