go to /etc/X11 and open XF86Config or XF86Config-4 and look for the line
in that section you should find a line
Driver "nv" (this means you're using the standard linux driver no 3d support)
Driver "nvidia" (this means you're using the NVIDIA driver)
you will probably need to install the driver
you can download it at
also download the readme.
it explains how to install it of search the internet for a HOWTO guide for you're distribution. For the installation of the driver you will need the kernel sources of the kernel you are using.
Once you got the driver up and running you can try to configure you're tv out.
It is explained in the README file of nvidia ( it's not that easy to understand)
i never got is completely working the way i wanted so somebody else will need to help you with that.