Do you not hear a CD or any other noises (bells, whistles, etc.)? Do you get any error messages stating that /dev/dsp is not going to open?
You might need to grant permission to the other usernames to access that mozilla version. If you downloaded mozilla to the root home directory, chances are no one else will be allowed to use it unless you grant permission to do so.
Mandrake is quite a good distribution for a newbie. However, if that newbie is interested in installing from command line and manually setting up his/her box and configuring/tweaking everything his/herself, then Mandrake is probably not the distro to go with. Mandrake has excellent GUI setups and configs, and is quite "point 'n click". Very easy, and it works well. If you're looking to dive deeper into the CLI, and get a bit dirty with Linux, then you'll probably want to try out another distro :cough: Slackware :cough:
I started with Mandrake 8.1 and it did everything for me, everything I wanted it to do, everything I needed it to do. After a couple of months, I decided I wanted to do everything myself, and do it my way. I then relieved my system of Mandrake, and installed Slack. Don't get me wrong, Mandrake is a really good distro and it's got everything you'll need to learn Linux--I just wanted to try a more force-yourself-to-learn-Linux Linux so I went with Slack--and I love it.
RedHat, Mandrake, and Suse are the distros that everyone seems to recommend for newbies. I've never used RH or Suse, but I did like Mandrake in the beginning. It was a great appetizer.