I have half of a drive which the partition manager guided me to unmount and format. Now that area shows a status of 'unmounted'. Discmount has been downloaded and run, and reports there are no files to mount at this time. Thanks for your time.
You don't say what distro you are using, or identify any of the names of those applications you're using ("the partition manager"...?)
However, try the following:
fdisk -l
lvscan
mount
Try those, post back with some output and we can take it from there.
Oh, also try: uname -a and cat /etc/issue to show some info about your OS.