I've asked this question last month, but have been away. Using Fedora 7, I ran a successful "at" job. When I tried another, I mistyped a command, and when I ran the "at" job, I got the message "Warning: at daemon not running". I have rebooted, but still get the message. Being new, I have no idea how to start the at daemon up again! Thanks in advance!

What is the output of

"service atd start"

Most dameons (not all) have "d" at the end of the name so you can often guess the name that way.

service is a special command in RedHat variants like Fedora that will execute the init scripts in /etc/init.d.

You can use "chkconfig -list atd" to see what levels it starts in automatically - for example:
chkconfig --list atd
atd 0ff 1ff 2ff 3n 4n 5n 6ff

This shows my server only starts atd in run levels 3, 4 and 5. It doesn't run in run level 2 (the first multiuser run level) so if my system were at that run level it wouldn't start.

You can find out what runlevel you're in by typing "who -r" or "runlevel".

If chckconfig indicated atd should be running ("on") for your current runlevel it suggests that atd died or couldn't be started. You'd want to examine /var/log/messages to see if you could determine why it failed or died. Of course running the above "service atd start" may give you an error message if there is something preventing it from starting cleanly.