2000 BMW 328 E46 engine Not switching off

I tried searching around, but couldnt find anything. I turn the car off with the key and it acts like I didnt do anything. The Car stayed running. So, I killed it by disconnecting the fuel pump switch and then everything stays on ( my fan, battery light, oil light,as well as my brake lights the only thing that turned off with the ignition was the radio). So I had to unhook the battery. I changed the ignition switch the week before (cos it was refusing to start and the car was behaving fine only for this to occur now) Please Help urgently as I am grounded as it is. Thanks