No one is able to log in. What can I try? Help!
You have run out of space on the root filesystem.
Bring the system up in single user mode and delete the files in the /tmp directory, then truncate /usr/adm/syslog.
Then check available disk space using 'dfspace' and if you have 5mb you should have enough to bring the system to multi user mode.
Then you have to either clean house or increase the size of the root files system