What cable and conections are you using? If you have a VGA to HDMI cable, those may not work work unless they are "active". Or are you using an HDMI to HDMI cable?
A note from one of the cable makers "NOTE: Your Video card must support digital signal output through VGA port function. Please consult with your VGA card's user manual for more information. "
Otherwise you need something like this http://www.walmart.com/ip/Aluratek-VGA-to-HDMI-Converter-Adapter/11997632,
or just connect to the VGA input on the TV, if it has HDMI, it should have VGA. You'd also need to run the audio cable over to the TV unless you want to hear the sound through the laptop.