stop mint 14 cinnamon from seeing my second monitor

[trenz]

I have my tv hooked up as second monitor which i use very rarely under windows 7. I will not need it under mint. The problem is if the tv is on when i start mint it changes the resolution of the monitor to that of the tv instead of the 1680 x 1050 of my monitor. When I uncheck "mirror displays" and try to change it the dialog box is off screen and I cant click OK. I have to turn off the tv and click "detect displays" before i can change it.
When I start mint with the tv off it is fine.

I should add that this doesnt happen every time

My question is can I prevent mint from even detecting the second display?

Thanks