A "PAO" warning is not related to a "no start". PAO is low brake pads and or a bad sensor for the pads. Being your car is a Sovereign, I bet when you step on the brake you are getting a red Brake light on the dash that is different than the one that will come on when you pull the emergency brake on.
As to you no start, have you tried spraying starting fluid into the air intake and cranking the motor? If it starts then you have a lack of fuel problem. If the car has been in an accident right before this issue started, you need to check the fuel cut-out switch. If that is good do you hear the fuel pump? If so check your fuel filter. If you do not hear the fuel pump, check the power to the pump. One wire will get power with the key on. The other wire is ground and will not have power. If you have no power at the pump, check your fuel pump relay, (you can swap a similar relay for testing), also check your fuses. If all of those check out ok and you still have no power at the fuel pump, a bad ignition switch can be a cause.
I realize this was asked years ago, but maybe this information will help others.
Wednesday, October 21st, 2015 AT 6:26 PM