1995 Regal shuts down

I have a 95 Regal w/3.8L. It started when I noticed that my headlights were flickering and seemed to be dimmer than before. There was also a high whirling sound upon accel.. I would be driving and it would just stall and all electrical systems shut down. I pulled over and turned the key. Either nothing happens or the gauges jump around and the locks go up and down, lights on and off, or it starts up. I have replaced the alternator, battery, and checked all connections under the hood. OH,, I also notice that it shuts down mostly when braking, turn signal, high beam, or reverse light. Is this problem in the steering column or the computer??? Any ideas out there.

I found the problem. I checked the fuse box pas. side under hood. turned it over and found corrosion. I pulled the 2 ign. fuses, the headlight fuse, and all others. cleaned , and put di-electric grease on the terminals. it runs great. The problem was that the tabs on fuses are aluminum. Aluminum rusts, but only a very thin layer. The rust is the same comp. as a Ruby or Sapphire gem. Its a very hard clear varnish like coating that preventeed them from good contact..