Sounds like maybe a bad motherboard or bus controller went out or something. Did you properly ground yourself when working inside? Maybe a conductive trail got damaged, but I doubt anyone would be that careless. Have you tried isolating the RAM to make sure it isn't bad RAM? I'm leaning toward a bad bus controller. Also, could be a damaged resistor or capacitor.

Summary: it could be anything. I'd try isolating the RAM first. And maybe try a different drive slot on the motherboard to see if that slot is bad.

Diode