Also more options:
* Resetting CMOS, nothing changes
* Installed a GPU (an HD6670) instead of IGP, nothing changes
The current board installed is a GA-B85M-D3V, previous board was an H81M-P33. (which I still have, but swapping is a PITA so I try to keep changing to a minimum when debugging) CPU is a G3220, and have tried a G3258.
PROTIP: When someone tells you building PCs is easy, they neglect to tell you what isn't is the fucking computer Kreminology that is consumer electronics debugging.
I've sworn off whiteboxes as a result of this charade - it's used businesses desktops that go off lease from this point on.