I'm getting power to everything. I turn switch to start an nothing no clicking n

My 1996 G20 Infinity won't start. New Battery, new alternator. Started great, went to a gas station to get gas. Turn off engine. Started up but stalled,so I turned the ignition off again and car will not start up again. No clicking, nothing. All the lights work and turn the key and nothing happens. Could it be a computer resetting problem? Lucky the gas is within walking distance and the car is still there. Please help me if you can. Thank you