Windows – Method to get windows left open on second monitor which is off back to primary monitor in Win7

I think it depends on you hardware configuration, if your monitor is connected via HDMI, DVI, Display Port or any other digital connector your pc "knows" if a monitor is connected and/or switched off, and so windows trys to set your second monitor as main display, but this seem to fail.

I know the exact issue you are having. Here is why Windows chooses your TV when you turn off the two monitors, or have all 3 off.

Without going into too much depth about how graphics cards and displays communicate, basically your receiver that the TV is plugged into is constantly sending an 'Active' signal to your HDMI. Normally, you turn off a monitor, and the graphics card knows, and it's all honkey dory. But, your graphics card isn't reading the 'Active' signal from your TV, its actually getting it from the receiver.

So, regardless if your TV is on or off, your computer thinks that it is indeed turned on, so it keeps sending it data. This doesn't change the primary monitor, but, if your HDMI cable is monitor #2, I'm and your primary is #1, then Windows is most likely dumping the windows onto #2 from #1 when shut off. And your computer thinks your TV is on, because it doesn't know better due to the receiver. Make sense?