Problem with my 1997 Chevy Lumina?

[Sarah]

The problem is that every time I start my car and begin to accelerate, reverse, brake or whatever, generally about 3 seconds after I do this the car makes a sound and slightly jolts. When it does this, my headlights dim and my radio will shut off but then restart itself and the two lights, the emergency brake light and anti-lock brake light will turn on. So, if I drive with these lights on, my car makes a high pitched grinding noise when I accelerate. Generally I have to restart my car to make them go away and sometimes the lights don't turn on if I get lucky and I've noticed that usually it's right when I touch the brakes that those lights turn on. Sometimes though, just the anti-lock light will turn on and sometimes just the radio will restart itself and even sometimes the radio will restart randomly while driving. The thing that always stays the same is the slight jolt thing where the headlights dim, this happens every time I start the car and begin to drive. So, can anyone tell me just what type of problem this is?