The same problem is duplicated in a different system with the same hardware and it still exists after my graphics card was replaced under warranty. Symptom: In Windows 7 with HDMi my screen regularly goes blank for about 5 seconds once every 5 minutes. It has to be a driver issue because this is what I've found out while troubleshooting. I have similar problems while connecting the AOC external LCD with the dedicated Gigabyte Graphics card via HDMI. As of now the newest driver from Intel (ver 15.26.) does not fix this. After uninstalling Intel HD Graphics 4000 driver, HDMI would work.

But after I restart, everything goes back to normal. So VGA and HDMI are selectable as different monitors in the relevant dropdowns. Strangely the HDMI cable starts working every time I re-install Intel VGA driver (the 'ding-dong' sound), and is recognized in the device manager and display settings. I tried unplugging/replugging cables, reinstalling drivers (Intel Graphics HD 4000), but to no avail. After the 'Starting Windows' screen the monitor complains 'HDMI no signal'.

The monitor displays HDMI picture fine from boot-up (BIOS messages/settings) up until Windows 7 loads. Soon after I got my hands on an HDMI cable, I tried to replace the VGA one with it. I have an Asus 247H monitor which I hooked up to a Gigabyte motherboard's (GA-Z77-D3H) on-board VGA port at first.

How to install asus vs247 monitor