Ok, I was in kind of a flurry when I posted that - now I've gotten a bit more used to the commandline and realize that some details are probably necessary.
Here we are:
Ok, I got the pb yesterday and it started up fine a couple of times. I passworded the hard drive and changed the permissions on it so that the owner is my username and no one else has access to it. Shortly after doing that (related?) the screensaver turned on and would not turn off. So I rebooted and it now boots almost directly to darwin and has me log in.
I see the grey apple screen and the "starting" screen with the blue bar, then right to the command line. So I enter my username and password then:
When I type "exit," it flashes a blue booting screen for about a second, then right back to the command line, asking for my un & pw again.
When I type "reboot" it says "command not allowed"
And I tried to run a fsck, but it does nothing. I type "/sbin/fsck -y" and hit enter and get another command prompt - no feedback of any kind.
So I went back and logged in as root, which now allows me to reboot, but it still won't run a fsck.
I rebooted holding "x" I also rebooted with the osx cd in the drive, neither changed anything.
And that's about everything that I've tried.
Has this happened to anyone else? Any suggestions?