I have just bought and installed an Nvidia 9500gt, hooked up my new monitor, and my old one, and only a single output is working at a time. I was informed that this particular graphics card was the highest grade dual monitor graphics card that my power source can handle. Could it be drivers, because of me having windows 7? Or is it more likely that it is the power source not being sufficient?
I just installed an nvidia card and to get the 2nd display to work I had to go into the Nvidia contol panel and enable the second display. Sorry I can't give further guidance, I am not at my machine right now. Right clight the desktop and there should be an Nvidia option. It is in there somewhere. It picked up my 2nd display model but I had to check the box next to it.