E30 aftermarket radio problems

[325iE30]

Maybe this has been mentioned before, but I seem to be having some problems. When I bought my 1987 325i, the radio did not work, regardless of how many times I enterd the activation key, which I still have, and matches up with the codes on the radio. After trying several times to get it to work, I finally pulled it out of the center console, and bought myself a Sony head unit. I installed the holding bracket and let the wires hang out onto the center console so I could wire the radio. I couldn't do it, so I just tucked the wires away into the metal bracket. When I went to go start the car, I guess the 12V constant sparked up. Anyways, what I am trying to get at is, after that little spark, I think I may have shorted something, becuase now, my spedometer, MPG meter, and my OBC do NOT work. I'm really upset because I just got this car on the road, and already, I am having problems. What could have I done wrong? Did I blow a fuse?

FYI, the stock radio I had was equipped with the "anti-theft" light.

Also, how do I go about installing my new head unit?

Any help is greatly appreciated.