Electrical problem I think

Hi I have a pontiac firebird 1987 with 6,000 miles on the engine and 140000 on the car itself. My problem is this the car doesnt have the original motor in it, it has a chevy monte carlo 305 with a carb 1987 in it, the car wouldnt start the other day so I had it jumped then a week went by and it did the same thing and it was jumped again then an hour later it didnt start again and now it wont take a jump at all, the battery is good it was tested that day, the alternator was tested also my starter solenoied has power. I dont know if it could be my starter but I dont see why I wouldnt have break lights or head lights, my ignition switch, my voltage regulator, or my alarm system killed it cause it has a kill switch on it. I have no power to the car at all alarm doesnt come on but the light will blink my break lights or head lights wont come on and I dont know what to look for anymore when thinking it was my alarm I took out the brain and tried to start it and then put it back in and im still getting nothing. Any ideas would be greatly appreciated.