Twenty-four hours later...
Anyway: this here, where I am speaking from? Is an apparently working solid iteration of the latest release of Ubuntu. And I have ported over my mail files from the previous unworking unsolid iteration of same, and I seem to have access to everything else over there, so yay.
A bolder wiser smarter man than I would probably make secure copies of everything, then wipe everything on this computer and start again from scratch, but hey. I am the definition of laissez-faire, and then panic. As you probably know by now. I never did stitch in time, which is why I'm dressed up to the nines.
Anyway: that has been an intensely computery twenty-four hours, including most of the hours from 4am lying wide awake and staring at the ceiling in a stressy kind of way; so now I am going to try to remember I'm a fiction writer, and (obviously) go out for a walk. In the bright sunny sun.