Weird. I would expect something like that on an older X58 (triple-channel DDR3, 2DPC) motherboard, not an "AMD A10-5800B", which I believe is a Trinity FM2 APU, although I'm not quite sure what the "B" at the end signifies, maybe the CSM version of the CPU/APU/platform?
In any case, I would remove the RAM sticks (after powering down and unplugging), and plug each stick in individually, and check System Properties, and make sure that it shows up, then try them in pairs, until one of them stops showing up properly, or they all start working. May also want to use an eraser on the contacts of the DIMMs, and/or some DeOxIt / contact-cleaner spray, on the DIMM slots and DIMMs. (Also use a can-o-air beforehand, if there's dust in them.)
Chances are, it's just a mis-seated DIMM, or heavy vibration in that location caused one to wiggle loose. (Had that problem with a cheapy P4 cast-off that I gave to a friend to use in a workshiop, whenever the train rumbled by, it stopped booting, until the DIMMs were re-seated. Was a PITA.)
Edit: It also could be a voltage or power issue, with the APU power planes responsible for the DRAM controller on-chip, maybe a VRM or cap on the board blew, and now it can't access that DIMM properly.