I was drinking water, neat. Sorry I'm so boring.
The motherboard switch was uneventful as well. I did think I had buggered the new motherboard with a screw at one point, but apparently not.
The only thing that changed was the boot sequence. I used to have more options, like a USB boot. It complained that it couldn't find the floppy or the second hard drive, which were not installed. I did add a floppy drive to the old motherboard, but left it out this time. It never had a second hard drive.