The car won't start
 

Hey guys , yesterday i was reving my g37x ( maximum 4500 rpm ) , and i took a look at the guage cluster and noticed that the rpm is zero even when i hit the gas . So i turned the car off , then tried to turn it on again , the key light turned on and the car won't start , i tried over and over , then i tried to unlock the shifter by a screw driver and i managed to put it at N , then i tried to turn the car with the key fob on the push start button .it did work, but i tried to turn it on again without unlocking the shifter it didn't work .so i had to do everything again .
what is the problem and how can i fix it ?