My 92 vette sat all last winter and I needed to replace my battery. After I replaced the battery I started the car, the stereo had a high screach sound thru the speakers, you could not hear anything except the screach thru the speakes. I had to drive with the stereo off to stop the screach. This did not happen before I stored it for the winter. Thanks for the help

Its interference from the alternator ,for whatever reason which i think is your problem but i could be wrong it could just be the radio has damp inside it and may dry out with use like have the heater on ,without hearing the noise its difficult to pinpoint exactly what the noise is ,yes their is a difference in the type of noise as to a clue as to what is causing the noise .