[jsc15]

Yes, I've tried unplugging everything from both the Chromebox and the monitor overnight. I still get the same result

in that case, I'm not sure what to suggest. I'd just bench flash it, but understand most people don't have the tools for that. Maybe try disconnecting the CMOS battery in addition to unplugging?

So I went ahead and opened up the Chromebox again to try and disconnect the CMOS battery, but before I got to anything else, I noticed right away that both of my RAM cards were unseated from the motherboard. I have no idea how it happened, but maybe one of my cats knows......Anyhow, after properly resetting the RAM and plugging in, everything started up like normal. Even my Elementary session was resumed, like nothing had ever happened....WHEW

Thanks a million for your help! Much appreciated.