Audi quattro 1994 won't start or even crank

The Audi wouldnt start when I got it, but all the
electronics in the car worked. I replaced the starter
and it started, I drove it around the neighborhood
twice. After parking in front of my house none of
the cars electronics worked when I turned the key
and it would start again. I disconnected the alarm
system and the electronics began working again,
but the car wouldn't start anymore and it wouldn't
even crank. Ive checked everything I've thought to
check. All the fuses are good, the battery cable is
good and the alarm is totally out. We just tried
pushing the car and throwing it in gear but we got
nothing... i have know idea, someone said they had
the same issue and the key fob was the problem,
but the key has battery and i dont know what the
button on they key does because it doesnt unlock
it. I dont know guys, please any other suggestions?