Two questions shift knob, and radio

one how to remove the shift knob in an 04 automatic, there is a screw off ring, but the knob wont come off, two i got this car used, and the stock radio needs a code to use after the power is cut off.  is there a way to get that code, because the radio wont work without it

Unscrew the ring until it comes off.  The knob should come off pretty easy after that.  I replace mine a while ago, so I don't remember the details, but I know it's not complicated.  If you go to the dealership (a decent one), they should be able to get you the code if you can prove that you own the car.  It took me almost a month, and trying 3 different dealerships before I found one that could figure it out.  Hopefully you will have better luck.