I recently purchased and Asus Transformer Prime, and I love it. However a couple of nights ago I was sweating bullets thinking it might be dead. I had charged it up but the device appeared unresponsive when I attempted to turn it on.
I decided to hold the power button down for about a minute to see if I would get a response. Sure enough after about 40 seconds the unit vibrated, though the screen remained off. I recalled that it vibrates when turned off. I left it off for another minute, then I pushed the power button and was greeted with the boot screen. A minute later my Transformer was back on line and ready for use.