Hello im trying find out why my 1999 ford explorer wont start or crank up

Stackkhouse

I have a 1999 ford explorer that wont start or crank up. The battery in car is Brand new and I also took the post off the battery when the car was started to see if it was the alternator. Had no problem with the alternator could it be my wiring system but then the engine? Please help

Stackkhouse

As you can tell I know nothing about cars. My neighbor said it could be My Car Alarm that's draining the battery. All I can say is I have to jump my car to drive it and as soon as I stop the car and take the key out the ignition my car is dead.