remote control not working?

i have dvd theater sound system(sc-ht880w)for many years .for some reason the remote stopped working. only tv vcr tv/av and numbers buttons only the red light comes up on the remote. the aux tuner/band dvd/cd rewind forward play pause etc., buttons dont work. i have changed batteries but no luck. so i have bought another new remote same one(eur7722xco) its also does not work, and doing same as 1st remote did with certain buttons working only the red light. please can you help me.