It depends what connections you have on your TV and laptop. If you have a HDMI port at each end then you can use a HDMI lead and both video and audio will be transmitted through the one cable. First of all, have a look and see if both your TV and laptop have a HDMI port.HDMI: http://en.wikipedia.org/wiki/HDMI (shows what the port looks like too)
If you have a VGA/DVI port on your laptop then you'll need a 3.5mm Jack Plug to 2 RCA Male Cable to transmit audio: http://www.thatcable.com/product/3-5mm-Jack-Plug-to-2-RCA-Male-Cable.You can buy a bundle here: http://www.thatcable.com/product/PC-Laptop-to-TV-Cable-Kit-VGA-and-3-5mm-to-2-RCA-Cable. That includes the VGA cable too (if you have a VGA port and not DVI).Check the audio ports on the back of the TV as you may otherwise need the other audio lead. Bundle here: http://www.thatcable.com/product/PC-Laptop-to-TV-Cable-Kit-VGA-and-3-5mm-Cable.