I used the built-in upgrade method, rather than pulling out a live CD and reinstalling. I've come up with two problems. First, it comes up without a mouse pointer. I can mouse, but I just don't know where I'm mousing. I can fix that short-term — open the Appearance module, change the pointer, lock screen, unlock — but the short term fix is all I can do, because not long after, I lock up with the screen blinking
Checking Battery Status. I remind you that this is on a desktop machine. No battery to check. All powered from the hole in the wall.
But that's not the annoying part.
The annoying part is that none of these issues come up when I log into another account I never used before. I logged in on Saturday. It's running fine still.
I don't want to have to rename and move lots of crap. I also don't want to reinstall from liveCD or live thumbdrive. But I don't want to keep it as-is, and it's hard to know which I want less.