Not sure it'll be much help but check this out:
Car no-start troubleshooting guide
Have you tried using your backup keyfob? and have you tried putting the key in the fobgina?
If I were you i'd cancel the appointment to trade in your car, it's sods law and it'll probably take you a trip to the dealership for them to check the error codes and solve the problem. If you cancel your appointment now, you can always come up with another excuse, you can always show it on Sunday instead?
Good luck.