i recently bought a 87 firebird with a 2.8 v6 it came with a aftermarket alarm system in it. couple weeks ago it started screwing up it finally drained my battery i pulled the fuses to the alarm system and put a new battery in the car and it still wont start now the starter motor wont even turn on

check right at the ignition, and where you put the key in. Sometimes aftermarket alarms have a kill switch style lockout that wont let you start the car unless the alarm is functioning properly and is turned off. have you tried to re-install the fuses to the alarm and see if that helps?