connecting to a TV using a HDMI

[elobire]

im trying to connect my computer to my tv to use it as a monitor using a HDMI cable, when i connect both of them it doesnt work.
is there any thing that i need to do to my graphics card to make this work(nvidia geforce 8400gs) or do i need to configure the computer itself?

 

[vladislav]

befor you plug your computer into your tv, make sure your refresh rate and resolution are compatible with your tv or you might have the tv on the wrong channel