Help set up HDTV w/ svideo+nvidia

I hope this is in the right place. I need technical help.
I can’t set up my computer to use my hdtv as a secondary monitor using dualview in NVIDIA (geforce 7900 card). It’s behaving strangely and I don’t know what’s wrong.

I have my HDTV connected with S-video cable and monitor via vga through dvi converter. I want to extend my desktop from monitor to tv, but the TV shows “No Signal.” Display Options/Settings show my desktop is extended, but the computer simply doesn’t connect to TV (so no picture on tv).
The clone view through Nvidia control panel gives a horrible picture on the TV, and all other options (view as one desktop and dual view) do not work. However, when I restart the computer, the TV works fine and clear at the startup screen. Then as soon as it hits the login window, the TV goes back to “No Signal.”

I have no clue where to start. What could be the problem?

Please help!

(I don’t know if this is even relevant, but the of monitors listed, my monitor is listed as “plug and play.” Should the TV be listed as this instead?)Thank you!

Are you certain that your card supports widescreen resolutions over Svideo?

S-video is only 480i (or 576i for PAL). The no signal on your HDTV is due to incompatibility resolution. Does your HDTV have HDMI input? or DVI input? It is better to connect your TV with a DVI-HDMI cable such as this one: