I have an Intel motherboard (DH67CL) that uses Intel HD 3000 video. It has two video output ports: HDMI and DVI. Both my monitors are DVI, so I have two cables: a DVI->DVI and an HDMI->DVI. If I plug a monitor into just one of these ports, things work fine. But if I plug monitors into each of the ports, the system startup screens show on both monitors, along with the "Starting Windows..." screen, but as soon as the system boots into Windows, the HDMI-connected monitor goes to sleep. When I use the Intel video control panel, the HDMI-connected monitor is not detected. How do I get a dual-monitor setup to work?
Well... first, according to the Product Specifications for your board, both the HDMI and DVI ports are enabled for POST when a monitor is attached to either (or both). So, right there, that's why they both seem to work at boot.
Furthermore, there are posts in their support forum like this one that indicate other boards like yours will support both the HDMI and DVI being used in Windows at the same time. To me, this implies that the reason why your HDMI monitor goes to sleep could be a resolution one. At least, that would be the case to me if the monitor was detected.
With this forum post, and a similar board, the issue finally turned out to be a driver based problem.
I was able to get this to work by switching cables. I know the HDMI->DVI cable worked fine, as it worked just find by itself, but that particular cable caused it to not work as a second monitor. The cable that didn't work had a "dual-link DVI" end, which has 24 square pins. To get it to work, I used a DVI->HDMI adapter that was "single-link DVI", which has just 18 square pins.
There are many people complaining of similar problems on Intel forums, so this may be a bug with the Intel driver, and a single-link DVI end might be required.
Normally this issue happens often when you do a Bios update, and you have 2 screens plugged into your computer. @ the windows welcome/login screen , you will notice 1 of your screens turned off.
Visit your motherboards website. Example: Mine is a Biostar B75MU3+ Ver. 6.x Make sure you get the latest onboard graphics driver.
What you want to do, is install the latest graphics driver. For example I have the Intel HD Graphics driver For a I5 3570k cpu 4000 HD
Once you do this. Right click your desktop, click screen resolution. you should see 1 or 2 screens, click the Detect button and Identify button. Then you will see 2 screens. @ this point of time... 1 probably won't be getting signal. But it will still show up in windows.
Make sure that you set the highest resolutions, and for the Multiple Displays: dropdown box make the tab say Extend these displays. also checkmark the box if you want the certain screen to be your main display.
click ok. Next in your Intel HD graphics System Tray / driver program. click graphic properties, and go into advance mode. On the left side of this new window... In the Display section, you should 5 choices, 1 is Multiple Displays. Click multiple displays, and on the right side, you should Operating mode ( make sure this is changed to Extended Desktop ) Make sure you set the primary display to the correct screen, and set the secondary display.
Click ok, and your 2'ed screen should now turn on :D