Pretty new to linux. The problem is that when I try to shut the computer down using "shutdown -h now" I get "command not found" error. Strange thing is it used to work just fine.

It's a superuser command - usually only root is allowed to use it. Jonathan

The command shutdown is in /sbin and usually only root has access to that directory... Lawrence

The same thing happens if I try to run it as root, command not found. It's right there in sbin, can't figure it out. I've been shutting the thing down with poweroff command.

shutdown (if I remember right - not at a linux box) is just a symlink to /sbin/halt (as is poweroff) you might have to create the symlink J

Perhaps /sbin is not on your path!!! Why don't you add that to your /etc/bashrc or /etc/profile and try it again... Of course, you need to log out and back in again so the new "path" would be in effect or just run source /etc/bashrc -or- source /etc/profile Lawrence