If your laptop has VGA out (blue one) then you'll need to have the same on the TV. If your laptop has DVI out then you can convert a DVI cable to HDMI and plug that into the TV. If your laptop has HDMI then straight HDMI-HDMI is what you want.
There's also the yellow S-Video out if your laptop is old, and that would need to be converted into a phono cable for the yellow Composite input on the TV.
All of the above will use the TV as the laptop's monitor.
If you're talking about streaming content to the TV then we're talking media servers and that's a different kettle of fish