6 hours ago, Bombastinator said:
That’s kinda bad. Also highly unusual. I hope it’s not a motherboard failure. That’s a nice old motherboard. They haven’t sold z97 that I know of in a long time. Replacing it would cost more than the computer is worth. I don’t have much in the way of suggestions. It could be the monitor or cable I suppose. I don’t see it as likely but I’ve been wrong before.
Not sure what was wrong, but the PC is now working again. When I revisited tonight the final code I saw on the led was 55, which has to do with memory not being seated, which made no sense because memory looked absolutely fine. Regardless, I attempted to wiggle the firmly seated sticks, and lo and behold the system returned to normal afterwards. Some minor fiddling with the sound settings and the system is now completely back in business.
I'd never used the system without a graphics card before (this is a high-ish end desktop system from 2014 transplanted into a Silverstone Grandia HTPC case), but it easily does what I need for the time being (play back 1080p blu-ray rips from a Plex server), so no need for the other video card at all.