This problem first occurred when my friend came over and we were going to watch a movie on my hard drive on my HDTV. I recently upgraded my video drivers. For the first time, when I went to the Nvidia control panel and selected DualView, then I tried all of the other settings (stretch, clone, etc). nothing happened, no picture on TV. This problem could have been caused by any number of things other than the new drivers, but it is the only thing I remember changing since the last time I used the dual monitor feature.
My video card has two DVI ports, one with a VGA converter for my CRT monitor, and the other with a converter to HDMI, and out to my TV.
Well, after uninstalling all my video drivers, and then using a program called driver sweeper to remove any traces of them in the registry or temp files, I reinstalled old video drivers I know for sure have had dual view working before, but I still can't get any picture on the TV, monitor is fine, and the Nvidia control panel does detect both displays properly.
I thought the port may have gone bad so I tried both the TV and the Monitor in each of the two slots by themselves and it all worked, but when I plugged in two at the same time, neither had any picture till I unplugged one of them. I restarted the computer knowing this may be the problem, but even after a fresh boot with both the TV and my monitor plugged into my card, I could not get a picture on the TV, but I do have a picture on my monitor. The Nvidia control panel does detect both displays properly. I have tried every resolution and setting on the HDTV, still nothing.
So for example, when I plugged in the TV first, and set it as the primary display, the desktop showed up just like it should. I plugged in the monitor, and no picture showed up on it. At this point the TV is still working fine. I wanted to get a picture back on my monitor, and the only way to do that was to unplug the HDMI adapter for the TV from the video card. As soon as I did that, the green light on the monitor came on instantly, and I had a picture on it within seconds. Then, I plugged the TV in again, and there was no picture on it, and there won't be until I unplug the CRT monitor.
I have tried booting the PC up with both monitors plugged in, after running a session with only one monitor, I have tried hot swapping monitors after booting up with one, or both attached, I have tried rebooting multiple times with both plugged in, its no use. I can't get both to work at the same time.