I am having the same issue, so I figured that I would reply to this discussion rather than start a new one. I just got a new NUC D34010WYK, and was able to load Windows 7 with no problems. I installed video drivers and audio drivers with no problems as well. I then updated the BIOS to version 0030 (latest, dated 9/19/2014). The BIOS update went fine, and asked me to restart the computer. After the restart, I never saw anything on my monitor again, not even the NUC BIOS post image. My monitor (Dell 27'' 1920x1200) recognizes when I plug in the HDMI but when no signal is seen, it goes to standby mode. It supports 1024x768 so it should see at least the BIOS post message. I tried plugging into my 32'' LG LED TV through HDMI, and got the same results.
I've tried both the Recovery BIOS and F7 BIOS update method (blind since I have no display, I just follow the button presses from Youtube videos). For the Recovery mode I remove the BIOS jumper and plug in a USB drive with the .bio file, then turn the power on. I see continous blinking of the power button LED when the update starts, then it turns on and off for 0.5 seconds for a few minutes.
I've tried booting with just the HDMI connected, in case any of the USB devices are an issue, but still no display at all. The power button LED does not display any error messages when I power up. Any ideas out there on how to restore the system?
I have another NUC, so I was able to confirm that all of my components are fine (ie RAM, SSD, Wifi, HDMI cable).