My machine suddenly went flaky, and then wouldn't boot -- I think some system files got trashed somehow. Booted to a Lucid DVD and copied my home dir to the second drive (215GB -- took a while), then started again with a fresh install of Lucid, this time creating a separate home partition. Made hcmc the first user, and created myself as another user. I'm now running updates and copying back my home directory to the new location. I'll get as far as I can tonight and then leave the machine working. Then I'll have to install a whole pile of software etc. tomorrow. Annoying, but it was time for a rebuild anyway; I've now got an ext4 drive and grub 2.