2000 Volkswagen Cabriolet brake light and ABS light

2000 Volkswagen Cabriolet mileage 82,000. I started the engine and noticed that the brake light and ABS light remained on and illuminated. I continued to drive approximately one mile when I also noticed that the air conditioner would not work. There was no power to the air conitioner of any kind. The blowers didn't work and it was if the car had no power for the switches to work. I immediately pulled the car over to the side of the road. As soon as the car was stopped and in park the car completely shut down and stalled. I immediately started the car again and the lights, this time, did not come on, but the air conditioner worked. I made a note to myself to bring it to the dealership for a valuation and possible repairs. Over the period of five days between the time it first happened and the day I was able to make an appointment the same problem occurred approximately six to eight more times. I have noted that when this happens it can be a various times during the day both when the car engine is cold and hot. Two days ago, I had the vehicle in for repairs at the dealership. I was informed that there was nothing wrong with the vehicle and they couldn't find anything wrong with it. I was advised to bring the vehicle back if I notice the problem again. Well, I informed the service manager that was hard to do as when the problem occurs the engine stalls. After picking up my car two days ago, the problem did occur again. This time, upon starting the engine I noticed the lights on yet again with now power for the air conditioner. As I was about to take it back to the dealership, I put the car in reverse and attempted to drive when the car stalled. I started the car again, the lights went off, and the car appeared fine. According to the Volkswagen dealership, service department there is nothing wrong with my 2000 Volkswagen Cabriole or nothing they can locate and repair. I'm not sure whether or not you have any information on Volkswagen but if you do, I would greatly appreciate any information you can provide.