Hey everybody. I tried running an upgrade from 8.04 LTS to 10.4 last night, and things seemed to be going smoothly. The upgrade progress was nearly complete, and I wandered off for a while to let it run. When I came back, I had nothing but an orange screen and and unresponsive system. I left it alone all night with the hopes that something would happen, but this morning nothing had changed so I hard restarted the system.

Ubuntu 10.4 appears in GRUB, but the system cannot boot and exits with a kernel panic and the message "vfs unable to mount root fs on unknown-block"

I was able to boot to a 10.4 LiveCD, and I can browse all of my files from there.

What can I do to get this system back up an running? I have dozens of user account and a lot of customization (it acts as a webserver with a wiki for a gaming website running on it, among other things), so I really really don't want to do a fresh install and lose all my data and customizations.

help?