Have you tried switching to the HDMI channel on the TV? If your HDMI port has numbers, like: "HDMI 1" or "HDMI 2" and you connect the HDMI cable to "HDMI 1" then you should switch the channel to HDMI 1. If you have already tried this, I am not sure if you have the icon buttons at the F buttons above your laptop near the ESC button, but try to press "FN+F8", so you can duplicate the screen. If you do not have this, try testing it with another laptop to see if the cable is broken.