Congratulations on your new toy . Does the button 'click' like the others do? You might want to unscrew the 4 cap-heads that hold the fascia on and see if the actual switch works with no buttons attached. This should help you ascertain whether it's the switch or just a button issue.

As to your second question. When on AC power the lowest state it can be in is standby. You can't turn it off completely. This is normal behaviour.