No Video output to external monitor or TV using GeForce4 420 Go

I have a Toshiba Satellite 2435-S255 with a GeForce4 420Go display
adapter. The computer works well.

However, when I attempt to output video to either the S-Video port or
the external monitor port (to LCD project), I get the computer
display, but NO VIDEO. I.e. if I play a video on Windows Media Player
or Real Player, the player shows up on the external display, but the
video is absent, black, nothing.

Toshiba says it is nVidia problem, since they don't write drivers.
nVidia says it doesn't deal with end users.

Is there any fix for this?

Keith