i believe i know what your problem is with the asus
i had the same problem (as have many other) and had to send mine back too due to starting up and shutting down.
what happened to mine was that i had also bought the "asus" protective cover with the keyboard built in it. do you have one of these?
if so, it (the "asus" protective case/keyboard) is the problem.
you probably had the start and stop problem, then removed your pad from the protective case and damaged the on-off switch. it is very difficult to get the tablet out of the case without it accidentally prying the tablet's backing off.
if your tablet is damaged, send it in for a new one. if you have a new one don't put it back in the case without first cutting out the on-off switch from the case and using a rotary file to open the hole where no part of the tablets' on-off switch is touching the case... too bad asus has not figured this out yet..
good luck