See if your TV and laptop have a serial cable hookup (most new tvs and computers do). Connect the two, put it on the right source, and hit the monitor option on your laptop.
Just want to point out in case you are led astray - Serial cable hookup won't do you any good, what is meant by lagomez is a VGA cable hookup. It does look similar to a serial cable, but is not a serial cable, and incompatible with a serial cable.
Some TV's do have VGA inputs, then all you will need is the VGA cable. I'm not 100% sure if the thinkpad has one but I would say 80% it has one - it is a business class laptop and this class almost always come with VGA video outputs for presentations.
Otherwise if your TV doesn't have a VGA input, then a converter like nink mentioned.