I too am playing around with the Transformer, and have had "random" crashes that took powering down, I hadn't worked out the zoom issue, so I thank the noggin and Kwiboo for their comments here... I know the thread is "older," but this input was helpful.
I will also say one of my Freezes is when the device tries to turn off video to the TV with the screensaver, so I have it dim to 100% and change sources when walking away is needed... I am able to reboot the device without pulling power by holding the power button something like 8-10 seconds then a 3 second press... Not sure if any of this would be helpful to anyone. 