After upgrading to oneiric, Ubuntu appears to be unable to start dbus correctly, which virtually renders half the system unusable. The startup error seems to happen rather early in the bootstages - and I have not yet figured out where exactly, or even what actually causes it.

I've tried to run dbus manually (sudo service dbus start), but no avail. I'm really not sure what could be done.

What are my options? Do I have to reinstall Ubuntu (my /home is not going to be affected, as it's a partion)?