2000 Ford Explorer won't turn over, lights all come on, jumping didn't help? Happened before after sitting started with no problem?

I know you proably have check this already but make sure the car is in park some times the shifter does not completely engage the switch so the ECI does not see the connection and this will keep the motor from starting. 2 if you have had any trouble before now with this vehicle doing this i would suggest you have the voltage in your battery check batteries will go bad and still leave you with enough voltage to run all the electrics and still not allow the starter to spin the motor enough to start, i hope this helps have a good day.

I had the battery replaced about 6 months ago.. But I'll have it checked once I get it stated again. I'll try to put it in Park good to see if that's the problem