Alternator/Electrical Question

[rtstrack]

When i have a fully charged battery, the car starts right up. After I drive it around for a little bit (just a few minutes) with the fan on, the battery drains and the car won't start. So it appears that either the fan is drawing too many amps or the alternator is not charging the battery. I changed out the alternator and then the voltage regulator, and the same problem persisted. So i started looking more carefully at the parts and a black wire (i'm assuming the ground wire) coming from the alternator was threaded to a bolt (which was holding the voltage regulator in place) that was on the inner fender. So I assumed that the ground wasn't any good, sense the bolt was on the fiberglass. I spliced the wire and grounded it to the frame. When I went to turn the key on, and you hear the click, I immediately see all of the dash board lights go on and a loud weird buzzing sound. Like electrical current or something. I didn't dare try to turn it over. Any thoughts on the sound or what might be causing the battery to drain?