First (and real easy). Use an ohmmeter to check the speaker(s) in question to see if the voice coils are blown. If the speakers show resistance (somewhere under 10 ohms) you should get noise. If you have no ohmmeter, you can momentarily touch the wires to a 1.5 volt battery. If the speaker is any good, you will hear a "pop".

However...that being said...Without more info, some speaker systems have their own fuses. THese could be the source of a no-sound problem. Sorry I cannot be of more detailed service.