From the symptoms you're describing, it sounds like the panel button on your television (volume down) is somehow always enacted. This would explain why the bolume button on the remote doesn't work, but the volume button on the televison does.
From here, that's the best estimate I can give based on the symptoms.
I'd recommend setting up a service repair for the bezel's button panel.
I have a Samsung LA32M51BS LCD TV. The last few days something strange is happening to the TV: When I turn on the TV, the volume is at 0. If I try ty turn up the colume, nothing happens (though the blue colored light on the TV is flashing). If I try to turn up the volume by pressing the + button on the TV itself, the volume goes up, but as soon as I release the button, the sound goes down to 0 again! I tried to take the batteries out of the remote to see if it's the remote that's messing up, but it didn't help. Does anyone know what could be the cause of this problem? Someone experienced the same?