You should be using the TV screens native resolution (I can't confirm as you didn't provide the model number - try the TV User Manual or Google).
If you are using the native resolution, and the image is "too big", it's likely the result of overscan.
Both nVidia and ATI have a setting in the drivers to correct for Over Scan. One of them actually refers to it as overscan, and the other merely offers the ability to make the image fit the screen. Both do the same thing (ie: ensure a native resolution input correctly fits the screen).
EDIT: nVidia Control Panel / Display Section / Adjust desktop size and position (allows you to center the desktop and adjust it's size to fit the screen).
NOTE: The above assumes that you don't have ZOOM or some other feature enabled or configured on that input of the TV.
If you are using the native resolution, and the image is "too big", it's likely the result of overscan.
Both nVidia and ATI have a setting in the drivers to correct for Over Scan. One of them actually refers to it as overscan, and the other merely offers the ability to make the image fit the screen. Both do the same thing (ie: ensure a native resolution input correctly fits the screen).
EDIT: nVidia Control Panel / Display Section / Adjust desktop size and position (allows you to center the desktop and adjust it's size to fit the screen).
NOTE: The above assumes that you don't have ZOOM or some other feature enabled or configured on that input of the TV.