product dropped and not working. Flashing a light flashing.
It’s hard to know what the fault is just from the info you provided to be honest.
You could connect the flight controller to your PC and use the DJI Assistant program to diagnose…
These controllers will not start the motors if the IMU and compass calibration are out of range so a re-calibration MAY solve the problem.
If you are not familiar with the software for the NAZA then come back to us and we’ll talk you through it.
Cheers
Steve 
Yeah. I am not familiar with the NAZA software.