Ok. I have a cool new Shuttle PC SZ77R5 with the Z77 chipset, an i7-3750 CPU, and the HD4000 on-board graphics. I have DVI and HDMI monitor ports. I have flashed the latest bios and have the latest HD4000 drivers.
The problem is that the HD4000 will not "see" the monitor in the HDMI port. It was working fine when it was the only monitor. When I added a monitor to the DVI port, the HD4000 "chose" this as the primary monitor.
At boot, the BIOS startup info displays on both monitors. The "Starting Windows" screen displays on both monitors. But,t when Windows finishes booting, the HDMI monitor goes dark. When I open the Intel graphics setup program, only one monitor is listed. If I try to setup using Windows 7, and auto-detect, only one monitor is detected.
Now, when I installed the latest driver package, the end result was that both monitors were working properly!! However, this is before I perform the re-boot that the driver installation program indicates is necessary. Everything works as I would expect. When I reboot the system, however, the second monitor "goes away."
I have changed the graphics adapter in my BIOS from "Auto" to "Onboard," and this has made no difference.
Intel tells me to deal with Shuttle PC, and Shuttle PC says it's a driver problem! Their best advice is to re-install Windows (7/64), but this wouldn't solve any driver issues. I did re-install the driver that came with the system, in case it had some proprietary aspects, but it is just a previous version of the Intel drivers.