Factory radio

Question

well i own a 97 BMX 740il, and my problem is i loan my car to my mother one morning and the radio was working fine (ive never had any problems with it) but when i got my car back later that day it was a frying sound coming from my speakers(similar to a tv snowing) and it was on all stations my CD changer didnt eve work just a frying noise. she said all she tried to do was change station to her favorite radio program, when i switch stations thers no pause like normal when switching just constant frying noise... any help would be greatly apriciated