If you are using a brushed DC motor, then (hopefully) the sparks that you are seeing are a discharge between the commuter and the brushes--this is normal. Another example of this is evident in certain electric drills; under low lighting, you can see sparks through the ventilation holes. If you are interested in this, you can ask at the EE Stack Exchange, or you can grab a textbook.
As for debugging your motor, try using a different voltage supply or use a multi-meter to make sure that your battery is charged. Motors do burn out, and this may have happened, but you should check the easy things first.
I found a resource that corroborates what I am suggesting: Debugging 3-Phase Motor Failure. Your motor is not 3-Phase, but the same idea applies. Measure the winding resistance with a multi-meter. If your coil has broken internally, you will get a very large resistance (unlikely because you are seeing sparks); if you get a very small resistance, smaller than the rated value, then your coil is shorted, which might explain the sparks.
I would do these checks first, then move onto the rest of your components, but if the motor is not spinning under a verified supply voltage, it's definitely toast.