I had this same problem. I could get the onboard graphics to work just fine and dandy, but the Nvidia graphics HDMI would give me the desktop, but I couldn't get any windows to show up and my tray icons were missing, I would switch back to onboard graphics and it would show up fine. I double checked the graphics driver and all that jazz. So, I emailed asus support. This afternoon I'll try to reinstall the graphics driver and if that doesn't work they recommended resetting the machine using a factory reset. So, that's where I'm at.