ok, so i want my laptop to display on my nice 21 inch sun monitor. It did this just fine for a long time by simply plugging it into the laptop, but then I tried experimenting with having both on at the same time. Before the 21 inch just displayed the same thing as the laptop screen and that was fine. But after I tried extending my desktop onto the external monitor (worked fine, but i didnt like it) I can't get my external monitor to act as a "primary" monitor anymore. It's just a desktop extension. The choice "use this device as primary monitor" is grayed out and I can't select it.
Brian. This may seem trivial to you as I'm sure you've already tried this. But on my notebook, I have to hit the function while hitting the monitor key (F4 in my case) to toggle between 3 settings.