I am having trouble getting my new Zorin 9 os to read dvd movies. 'Unable to mount files' is the error message I receive.
 

I am having trouble getting my new Zorin 9 os to read dvd movies. 'Unable to mount files' is the error message I receive. While a newborn to anything Linux, I am not computer illiterate but I do have limits on the time I have to learn a new system. I am sure the documentation for all I need to know is available, but again the time to find it all is not mine to spend. Can anyone point me to a comprehensive, downloadable laymans guide to everything Linux?

A single complete guide is a bit of a stretch. There are too many facets to Linux (or Windows or MacOS for that matter) to fit everything into one book, however fat that book may be.

You can start at The Linux Documentation Project. Much of the stuff there is older, but, as it tends to be command line-oriented, it's still quite valid. My go-to reference when I started with Linux was Garrels's Introduction to Linux. I still have a copy on my bookshelf.

You can also find a wealth of books as O'Reilly. Much of the older stuff is available for download, but you may have to hunt around to find it.

You should also learn how to use the man pages. Note that they are not designed as tutorials, but as references. Enter this command in a terminal to learn more:

As regards the DVD issue you mentioned, it would be helpful to know whether the DVD is a commercial DVD with DRM and whether it's NTSC or PAL, as well as what program you are trying to open it in. Furthermore, generally, if you want to play a DVD or an audio CD, you don't "mount" it as a file system the way you "mount" a USD stick'; you open it directly into a media player.

Also, if you have a DVD player, test the disc in it to verify that the disc is indeed readable, if you have not already done so.

I will suggest that, if you have not tried to open the disc in VLC, give that a whirl; generally, if it won't play in VLC, it won't play in Linux. I would expect VLC to be in the Zorin repos.

If you can't print anything on your printer or use the CDROM it could be a permissions issue.
You have to belong to that group in order for the user to have privileges.

Here in the output I had to add the user to all of these groups and until I did I couldn't use anything.
I used the usermod command to do it.
You can find out if your belong to all of the groups by typing 'groups' in the terminal.

Are you trying to watch commercial movies?
Have you installed libdvdread and libdvdcss?
Right click the movie icon and select from the options. You should have several options including VLC.
Zorin is basiclly Ubuntu under the hood so if you don't get a solution here, check the ubuntu forums.

http://ubuntuhandbook.org/index.php/...-dvd-playback/

You probably just need to install multimedia codecs. See link above.

how exactly are you trying to read (i assume you mean watch) that movie?
have you tried VLC, open the media player first, from there open the device?
is your dvd encrypted? you might need to install (via software center/ package management) some extra libraries/codecs, iirc it was libdvdcss.