2002 Isuzu Rodeo

I have an 2002 Isuzu rodeo 6 cylinder. Friday it kept loosing power to everything except motor no radio, power windows, no gaubes worked, no a/c, and automatic transmission at first would work as long as you changed it manually then got to where it would not get out of 2nd and only go about 20mph. It had to be jumped when shut off, parked it for the night and next morn went and put a diff battery in it and it drove normal to auto zone they tested my old battery said it was good then checked battery and alternator in it and said the alternator was going out and it was done draining battery in it before I got back home everything quit working but motor. I went to take out old alternator and found wires that were corroded so I fixed them and reconnected them when my wife went to crank it, it arced bad out of old alternator then no longer would even try to turn over. Took old alternator to auto zone and when they tested it a red light came on there machine and then machine shut off so it was def bad. I went and put the new one in with no problem, but still nothing but headlights and dash lights work. There is no clock which is always on even with no keys, no radio, no a/c, no tail lights, no door or dome lights, and will not even turn over at all, battery is fully charged, alternator is new and tested good, and I tested all fuses on dash and in fuse box under hood and nothing was blown, but still only have headlights, and dash lights, and can hear what I think is fuel pump cutting on. Does anyone have any idea what might could be the problem and how I might can fix it, its the only car my family has and I do not have the money to take it to a mechanic