please help me probs with the radio with saab 9-3
 

HI to everyone, please can anyone help me i got some probs with the radio with my saab 9-3 from 2006 tha radio is totaly off i can turn it on nothing on it work i had some water in tha car ones and i think ive ¨killed¨ the small box under the seat but im not sure and i dont really know what to do please does anyone knows what it could be!!!!
thanks a lot!!!!!!!!