Samsung LCD TV has no picture or sound?

My Samsung LE37R87BDX LCD TV was working fine, I turned it off and when I tried to turn it on again, nothing, no picture or sound. I took plug out and left it for a few hours and when I plugged it back in the standby light comes on but when I try to put channel on by either handset or main switch the standby light goes out so the picture should come up but nothing, no sound or picture does anyone know what's wrong