try one of the function keys, hold shift and by the numbers on top there should be a symbol with a blank and blue screen next to each other, this sends the visual output through your cable to your other vdu
Some manufacturers wire their TVs to take both on the RCA plugs, but most put the RGB input on a SCART socket. If your TV's RCA inputs are YPbPr only (check the manual) you're going to have to use an RGB enabled SCART socket. Even then its not garaunteed to work. VGA is an RGB/HV signal, if the VGA port doesn't detect a signal on all pins it should it may assume the cable is damaged and refuse to output on that source.
If that is the case, check if the laptop is an ATi graphics chipset. If it is connect to a PC monitor and see if PowerStrip (available via google) can get the chipset to output an RGB signal without a verticle or horizontal sync.