Looks like the graphics card died on my 12 yr old, "never skipped a beat", PC Specialist desktop. I'll look into what's occurred (any tips on where to start diagnostics welcome - I've got output, but blank screens). But it's my main business machine, so I can't afford to hang around. More likely I'll buy a new one (using my laptop for the next few days) and then try to fix the old one as a backup, and learn a load of stuff about graphics cards in the meantime. I'm looking for an office PC, heavy on Zoom for training,and Vlog editing, with headroom for casual gaming. Any comments on the spec I've quickly thrown together for starters. [Been a long and stressful day!!].