Depends on the laptop & TV (sorry to state the blindingly obvious).
The laptop should have a VGA or DVI or (if it is new) HDMI output socket - you need a matching socket on the TV (unless you can find some sort of converter cable/box) and a cable.
Then you need to tell the laptop to use the TV as an external monitor (usually one of the function keys will do that).
Although the VGA port will only give video, for sound you need another, different lead.
Exactly which one depends on exactly what type of connection the PC audio in connector is on your TV.
(this question gets asked about twice a month, and nobody ever seems to think it's relevant to state any details about the laptop or the TV in the question!)
Thanks all.
Chuck, sorry but we innocents tend to assume that there is some industry standard in force, which governs all computers and TVs (and their socket provision). Specifying details of make and model, to establish sockets, should therefore be entirely superfluous, unless we are talking in terms of the equivalent of something Logie Baird was making in his early days.
We don't have to say whether our cars have hot tube ignition, the engines have side-valves, or they are Stanley steamers, in asking about them LOL They are all made to EU standards for our market.
Fred, some laptops come with HDMI sockets to connect directly to the tv, others have VGA, S-Video, composite or DVI connections.
Televisions may have HDMI sockets, one or none of the above.
So to give proper advice, Chuck is correct and lots of information is needed.
Some laptops don't have a 'dual monitor' facility and cannot be displayed through the tv, by the way. If things were standard there would not be so many models from each manufacturer.
I did this with only an HDMI cable just check laptop and tv has a HDMI slot and away you go. Don't buy expensive cable cheapo from tesco works equally as good.
I've got a late model Sony TV too, and it can be connected to the internet via an ethernet cable or wifi. It has all the software for youtube, skype etc., internet TV built in.
Agree with fruitcat about the cable , even a poundstretcher one is fine .
After all its a digital signal - 1's or 0's , black or white , off or on etc.
"We don't have to say whether our cars have hot tube ignition, the engines have side-valves, or they are Stanley steamers, in asking about them LOL "
What a silly remark. Anyone giving technical advice on your car needs to know the make and model so that they can provide appropriate advice. Believe it or not, there are different kinds of engines, transmissions, steering mechanisms, braking systems, etc., etc.
Because I live in a bedsit with limited room I use my 65cm LCD T/V as my Desktop Monitor. It is connected ( as Chuck says ) with a VGA cable from P/C tower to T/V & external speakers from Tower Audio Out. When I switch the T/V on I have the choice of T/V,DVD,P/C or A/V Freesat. & it works a treat.