I am quite close to throwing my television out of the window, maybe you can help stop this.
I have an 8800GT with two DVI out slots and a little round hole into which I can plug a round plug with three RGB component cables coming out of it. My TV is a fairly crap old CRT, which only has two big hefty scart sockets and ye olde composite roundy extravaganza.
So what i thought would be snazzy would be to purchase a RGB component cable

I have now hooked everything up and "extended" my desktop from my monitor onto my TV which has resulted in my TV displaying a handy black screen when I select EXT1 (the hole into which the computer is plugged into) which is no different to what it would display if no cable were plugged in there.
If I go into EXT SOURCE under the menu option of the tv, i can select this option:

which doesn't seem to do anything, i don't even know what it means, and that's the only thing I can change on my television.
On the PC side of things, if i click advanced and go to the nvidia control panel, i can select lots of different resolution options, none of which work, and that that seems to be my lot:

Could it be something to do with the pc sending an HD signal to a SD scart plug? I really do not understand these things. Any help would be most appreciated.
I also posted this in the DVD, Home Cinema forum, but it seems to be somewhat dead.