2000 Ford Mustang

Lets try and start from the beginning
engine crank but will not start

turn key on, do you have check engine light on you should if not check fuses, relays, wiring and ignition switch

do you have security light on and blinking if so check for codes if not
open hood and check for spark
have a helper crank engine for you as you check for spark
if have spark check for fuel and fuel pressure
no fuel check fuses and relays
check if inertia switch was tripped