I have a 97 Nissan Maxima SE and the radio has completely stopped working. It started with the lights going on and off on the system, then the radio would fade in and out. Then if I tapped, well sometimes if I was mad

, hit the dashboard it would come back on. Now the radio wont work at all, the tape player doesnt work, the CD player is the only thing that works and only the last three buttons on the system work, the first three dont. Is there anything I can check or should I just take it in, I am sure this wont be cheap.
thanks!