I have a Samsung DV3 32" television and the remote control no longer changes channels, except for the volume control. It also no longer switches the tele on and off.
Make sure the remote isnt switched to vcr functions,
clean remote only with Isopropanol Alcohol or lighter fluid.
check remote by pointing it at a mobile phone camera and see if the infra red led light flashes.
amg, June 2007
You could take it apart carefully and clean the printed circuit board under the key pad and the underside of the rubber keys. Use a damp cloth with ordinary water but ensure that it is thoroughly wiped off and dried afterwards.