Can't set dual monitor.

Here's my problem:

i get into ATI catalyst control center, either advanced or easy setup, when i try to set adual monitor interface... well i neeed two displys, which i have: my tv and my screen. But i just cant set them up at the same time. There are two little boxes where you're supossed to drop the tv's or the screen's image and they will work in a dual monitor setup.

Box #2 is not available, it just shows up itself as gray and nothing can be done. If i click the second screen on the dual setup it asks me if i want to enable it, if i click yes my main screen just goes black for a second or 2 and then nothing happens again.

At desktop > Properties its just the same, i click enable secondary device and the screen flashes black and the "enable secondary device" box unchecks again on its own.

I really want to do this dual monitor setup as i like to watch videos or play videogames at the tv while i chat or work at my main screen. Thats something that at least i could do with my old laptop.

For further detail:
ATI HD2600PRO 256mb ddr3
TV via S-Video
Monitor via DVI adapted to VGA
Catalsy driver version: 8.591.0.0
Catalyst control center version: 2009.0225.1546.28221

Please if you need more info and are willing to help me ill give it all out if i hadnt already. Thanks to those who at least read it

Almost forgot: Also tried with ultramon, results: nothing.

The monitor is connected with a dvi to VGA adapter to the dvi port
The tv is connected in the S-Video port with a S-Video to RCA cable.

Both screens are dettected and i can even do quick screen switch with a short cut i made for this. I do play games at my Tv and watch videos, but i can not use both displys at the same time, I've got no ideas left on what to do.

S-video and RCA kind cables are analog.
Vga outputs are digital.

i dont know if that is something to worry about, but it shouldnt as the card supports boths very well.

My TV is pretty old, it doesnt even have an S-Video cable, The s-video cable is connected to the video card, but it has an adapter to RCA connector

Sorry, i dont get what you're trying to say