I have the same issue that all in this post, this mother is a ****!!!!! but i writte my research.
After many many many trys to get video back, i can see that the solution for get back video is unplug the mother from atx or turn off the general power of the power supply for 5 minutes or more.
If this not work i need put the ATX cable with green and black wires in short circuit, you can see that the fan start to work but no video and nothing in the screen, do this for 1 minute and after 1 minute stop to shotcircuit the ATX wires and unplug from the general power, again wait for 5 minutes and try to turn on again the mother board and many times it work for restart the video.
when the mother back to life, it work fine for many times, restart and power off and sleep ok.. but some days stop to work and i need to this again.
some times only need cut the power for 5 minutes, but other times i need put in shortcircuit the wires...
i hope this help to some body, and that somebody can discovery how fix this mother not only for a few moments