A clutch job was performed on this car

A clutch job was performed on this car. Car was running fine before. The car was driven for approximately one week, then it began losing a little power and misfiring a little. Eventually there was no spark, the injectors would not open at all. It would start every once in a while and run perfectly. After it ran, and the car was turned off, then it would not start again. Then periodically it would turn on. But now, there is no spark at all. Crank sensor, cam sensor are working. This has been taken to an Infiniti dealership. They said it was the timing chain, which definitely isn't the case. That has been checked as well. It is believed this is related to the security system as all the other systems seem to be in working order. We were told by the dealership, if the system is working correctly, the car should start, but the possibility was mentioned of a faulty security system. Would a reset of the system help? Or would this require completely changing everything related to the security system out?