After changing the alternator, nothing happens when I try to start the car.

Hello everyone,
I hope someone can help with my problem. I'll have to make a long story since it all started about 2 years ago. After a very cold night, I had to boost my car, since that happened I had to boost it pretty much everydays until I tried unhooking the positive wire, it worked! No more need to boost the care (problem not solved but I saved time and trouble starting it again) I planned to keep it like that until spring when I would check what was draining the battery. But with the warmth, the problem dissapeared. But this winter it came again, I started unplugging it again and it worked for awile, until last week, I had to boost it to go work, and again to come back from work, the day after again, I boosted it to go work and again after work to come back, the car started but when I got in and hit the gas and steered the wheel (which came hard to move), 3 lights opened in the dash. The handbrake, the ABS and the power-steering malfunction. I drove like that to my home, few kilometers away from the job, every time I gave more gas and steered quickly the light came back on and went off right after, I opened the radio and it kept reseting when I was giving more gas and steering again. I got lucky in my badluck, just in front of my place, I braked, put the car on reverse to park it and noticed the car died, I tried to restart it but nothing happened(Nothing at all). I pushed it to park it and then talked to friends about it. As i tought myself, they said it would be the alternator that died and that I was running on the battery at the end. And that I probably would need to change the battery too. I got a rebuilt alternator, plugged my battery inside on a 6 amps charger and left it for 18 ish hours. Instelled the new alternator and the battery, still nothing happens when I try to start it, not even the solenoid clicking....just nothing. But everything else works, lights, wipers, radio, everything. Tought it could be the alarm system's kill switch, but my remote is still working fine and when the alarm start buzzing I can stop it with the remote so I assume the the killswitch would not be the problem. I tried to jump the battery and it failed, then I tried another battery directly plugged to my ca...same result, when I try to start it I just hear the "wooom" which I think is the fuel pump, but no clicking or anything else. I hope someone can help, I'd like so save some money by not towing my car to the garage. Anyone got an idea?
:bang

Multimeter the battery at rest and while trying to start. Check grounds. Double check all connections are tight and clean.

could be the neutral safety switch

Try to start it in neutral and if it starts its probably the neutral safety switch. I had to get mine replaced