Disable "Machine on-off" button

Hallo everybody,
I am a new user from Greece
Well what is my problem.
I did pncconfig my 7i96s Mesa card
(first doubt: my motors iHSS60/36 are from 800 to 40000 pulse/rev and linuxcnc have a limit of 1000...so microstepping?)
I had connected only one motor and I launch linuxcnc.
But there the machine on-off button is disabled.
I am sure its something stupid but I cant find any relative topic.
It has to be anything declared (min 3 axis) mounted to work?
Could anybody help? Thanks