Anyone been able to disable a display connected to a 7970?

[Elmojo]

Hi all,
My rig has 2 GPUs, an older GTX480 that is my primary gaming and desktop card, and a 7970 dedicated miner.
I'm running 2 monitors on my GTX480. I had to plug in a 3rd monitor to the 7970 to get it to recognize, but now it's extended my desktop onto the 3rd monitor.
I don't want this, since things keep getting 'lost' on mon 3, and I keep it off to save power.
Is there a way to disable that monitor in windows, but still let it be connected to the 7970 to keep the card live?
I tried simply disabling it from the windows display panel, but that does something to my 7970, because all the readings on the sensor page of GPU-Z drop to zero.
Thoughts?