Hi, I have in 1996 Volvo 960 140,000 miles on it. my AC is not working at all, the blue light around the control switch does not light up or flash. I just don't really know where to start. Help please

I started to notice the smell of burning oil when I stopped hard, and only when stopping. I Looked under the hood no leaks, that I could see anyway. Well yesterday I had to stop really fast when the car came to a full stop the oil smell was back, then gray smoke came out from under the passenger sid...