First, verify that your LCD TV can be used as PC monitor. This is far from automatic.
Secondly, if first was good, then your TV either has a DVI connector or a PC-compatible HDMI interface. If it is the latter, you will need a DVI-HDMI converter (small piece of cable). If the TV has DVI, use it to connect to your video card.
Thirdly (actually this should be second, but I had almost forgotten about it), make sure your video card has a DVI interface.
Caveat: Your PC will need to be close to the TV for both DVI to work properly (without costing you a lot).
Also, remember that depending on the native resolution of your LCD TV (1024x768, 1366x768 or 1920x1080) you may lose some resolution. If your TV has not been "calibrated" for PC use (special mode or user-configured), the image will not be sharp since the goal of a TV is to display "real life" images that need a bit of "blurriness" to be accurate and beautiful.
THE GOOD THING: If all the conditions are right, you are going to have a heck to a PC monitor!
