2001 honda civic car stereo not working...?

hi! HELP!...COULD YOU HELP ME PLEASE..i have a problem with my 2001 honda civic stereo..i bought this car a couple of months ago and the radio is working fine and then suddenly it died..the first thing that comes from my mind is to disconnect the battery because i thought it might reset the radio and it works but the thing is...WHENEVER I START THE CAR the radio is gone again..totally out no lights no time(clock)....i tried it many times and still the same thing happen. Then i try to disconnect again the battery and put it back, this time not starting the car just letting the car stereo play for long time THE RADIO IS WORKING FINE BUT THE CLOCK ON THE RADIO LCD IS NOT... and then again when i start the car the radio is dead again...

thanks...