ok
on some i got it by just touching the button,others i hold it past the blinking as per the asus instructions
only then i got it going
YouTube - ‪ASUS MemOK!‬‏
tht guy holds it just enough.
give it a touch first. no go?
then hold it like you wont let it go..30-60 secs.
worked for me at least so far :D
edit : the only way it works as per the manual is if the light(red) is lit and you hold it right then and there. it will have the same effect(shut down,reboot) even if the light is not lit.