This is a long shot, but sitting at a fairly new Gigabyte GA-MA69GM-S2H using only the onboard graphics I hit some function combination (space limitations lead to a notebook-style keyboard choice with FN where CTRL should be) and the graphics died instantly and the MB is now doing its "continuous long beeps" indicator for an improperly seated graphics card. There is no graphics card, so presumably it means that the onboad graphics has a problem.
I've rebooted, cleared the CMOS just in case, and checked DRAM and cable seating, KVM and monitor so it looks like it died coincidently, but if anyone knows of any magic keyboard combinations I might have hit that might just have shut it off I'd love to hear about it.
More aboutkeyboard commands disable onboard graphics
Tried it without the KVM?
Yes, and also tested the monitor, keyboard and mouse with the other machines in the stack.