Well I should have known I'd jinx myself when I mentioned in my last post that the strange, hanging at boot problem has solved itself. Just this morning, the day after I posted, the thing just hung at the boot splash screen. A quick control-alt-delete got the thing rebooting, and it all started fine after that. Looking in the log file viewer revealed nothing out of the ordinary; checking the ubuntu forums showed up nearly nothing, apart from the fact that it happens to other people too.
I say nearly nothing, because I did learn one thing. If you hit escape while in the boot splash screen, the pretty graphics go away and the boot messages come up. I now want the machine to have problems at boot, so I can try this and see if anything interesting appears. Yeah, reverse psychology. I want you to fail at boot, all the time!
(Originally posted June 28, 2010 on my other blog)