remote issue with new digital box

Hi, I received a free digital convertor box (for one year) so that my non dvr tv can receive signals. I was able to program the remote where it will turn the tv off and on and also change the digital box channels. My problem is mute and volume increase/decrease does not work. It did at one point but now it doesn't. I tried recalibrating the remote by putting in a new code. No luck. The tv is new from Christmas(LG LED 32"). Another problem that just started happening a few days ago is when I turn the TV on for the first time in the morning I get (no signal) on the Tv and then the cox box eventually reboots itself and the tv picture comes on. Thanks Pat Cyr South Windsor CT.