92 DeVille Starting Problems. HELP!!!!

I have a 92 DeVille with 131K. About two weeks ago, the car began to stall out a few times while driving, I would just throw it in neutral, then turn the car right back on without problems. Then I have an issue where the car won't turn on AT ALL! There is absolutely no power to the car, no lights or anything works. I can wait a few minutes than it starts up like nothing is wrong.

My mechanic told me it was the alternator and I spent $200.00 to replace that. The problem is back again just as bad as it was before the alternator. The battery is only about 2.5 months old. I checked the battery cables and they look fine and not corroded over.

What could this possibly be? I don't want to take it to Cadillac and be raped with labor charges. I can't afford to put much money in this car.

Please help!

I tried to jump it and would not work. Still no power. As I was taking the cables off the positive terminal, power came back and started up.

1) I believe this needs new battery/terminal cable mounts

2) If the positive was a bit corroded, I think this would have cut the power to the alternator causing the car to stall

Does this sound like it makes sense?

HELP!

sounds like you tracked it down, Id replace both cables just to be sure, good luck :)