DevilsAddvocate

I have a 89 TBI 5.0, I get home just picked up my open element air cleaner 14x3, put on like YES finally gets some air into it. Install what not, jump in the Camaro, put the key in the ignition, turn, notta damn crank. Im like o no, try again, nothing, check all my battery connections no problems there. I got one of those alarms you hook up to the battery so I disconnect that and try 2 reconnect, its supposed to beep, to tell you its armed what not. Dont get a sound, pull my moms car up next 2 it, connect alarm to her battery, beeps so the alarm works fine. So at this point I was thinkin battery, So i try 2 jump the maro, nothin, I try jumpin her from the battery and from the battery cables cuz I donno maybe the batterys messed up, still nothing. Lights dont work, power locks/windows all that good **** dont work. Starter doesnt sound, the key left in the ignition sound doesnt go, nothing at all works. I havent had a real decent amount of time 2 look at her since it got hella dark quickly. Was already dark when i finished install. So gonna have 2 take another look 2morrow, what does everybody else think the problem could be? Ground for the battery was fine before, but it doesnt seem to be giving my alarm or any other accesories that I know to be working any power. The starter, has acted up in the past I mean its all ways worked, but it would take a second, its slow at first then speeds up and car fires to life hope that explains it. Thanks for any help in advance.