MSI K9NGM3 Series Manual page 129

If you have a TV connected and it is not being detected, you can check the "Force
TV detection" box in the Tools field.
Important
Please note that the TV-out function can not work with the onboard D-Sub out
function, that is to say, you can not use the TV-out function and the onboard
D-Sub out function simultaneously.
TV-Out Function
E-7