Yesterday I have connected external display Asus VW192C to my laptop Dell XPS 14-L421X via HDMI-to-DVI-D cable. And it worked perfectly fine from start. The day after, Asus screen went blank showing "No signal". Every time I connection/disconnection cable or power off/on the display it says "No signal". And I didn't change any system configurations meanwhile. To troubleshoot the problem, I have tried to connect laptop to TV (hdmi-to-hdmi) - it was fine. I've tried to connect a different laptop to the display via the same cable - worked fine as well. So its obviously something on system level, either Windows or graphics drivers. Also it seems that Windows still see the external display (I can move mouse pointer away from the main screen in Extended mode), but there's just no signal. Any ideas? What else to try? PS. My laptop has 2 graphics cards - GeForce 630M and Intel HD 4000 using NVidia Optimus technology. I have updated to latest Intel and NVidia drivers, still didn't help. PPS. Although I shouldn't have updated (from Intel support): "our Intel generic graphics drivers from the Intel website do not support using both Intel Graphics 4000 and NVidia GeForece GT630M". Nevertheless, it should not affect connectivity to additional display.