I would say 99% for sure you have cooked the ULN2803 chip - IC's don't take kindly to being shorted or having voltages applied to them incorrectly and will evaporate in milliseconds! It is mounted about the centre towards the bottom of the CPU board. Fit a socket so it is easy to replace next time. If you don't feel comfortable about removing the IC and fitting a new one there are plenty of talented people on this board who can help you.
