Radio/tape Cd Player problems of the 2013 GMC Acadia

While on a highway using the intellilink navigation system suddenly the icons from another screen, the radio controls appeared over the top of the navigation map. I couldn't see the map anymore and didn't know when or where to turn. Nothing I did fixed it except to pull over on the side of the road and turn off the car and turn it back on again. This is very dangerous because one might turn on a one way road or in to a crime ridden neighborhood.

I was driving 50 mph on a very busy city highway when I heard what sounded like a truck putting on air brakes but no trucks around me, I felt shuddering under my foot. Suddenly "service charging system" or something like that flashed on my dash and I lost power steering, acceleration, everything. I was able to pull hard on the wheel to get into the right lane from the center lane, there was no shoulder to pull off on. Brake was hard to depress, it felt like it was all the way to the floor. I had power from the battery, it was sitting at 12 volts. I turned the vehicle off and restarted, I couldn't hear if the engine was running as the cars going past were so loud, but the radio was on and dash lit up like it had started but it would not move. Called my insurance and they sent a tow truck. While turned off on the tow truck, the outer rim of the head lights and the main headlights suddenly illuminated and about 5 minutes later they went off. Dealer was able to start it, but not move it. I dropped it on Thursday, by Friday they still didn't have an answer and I have to wait till Monday. I had one of my children with me when this all happened. It was very scary. There are just over 36,000 miles on my Acadia. My husband also noted that the day before when he tried to start it, it didn't start right away, it paused, he left off the key and about a second later it finally started.