My Sansa 4G Fuze is stuck on FM, one station, one volume. I can’t change the volume, station or switch to any other function. I have to hold the off switch for about 12 seconds just to turn it off. I think this resets it, but it doesn’t. Turn it back on and it is still messed up. It is about about 2 years old. Bought it for wife and she is finally using it and this happens!
You could try reinstalling the firmware (has to be done manually). But it could very likely be a hardware issue. Does the click wheel feel as if it’s operating properly?