Amanallus, RedHat 9 is old. The distribution was split a few years ago. RedHat is still available as an Enterprise version, the personal version is now known as Fedora Core, now at version 6. Mandriva Linux is another RedHat RPM based distribution worth a think about. Now at 2007 release. If you have an ISO file, then it must be burned to either a CD or a DVD, using Nero, or some other burner application, to burn a bootable disk. This disk is then used for the installation. An ISO file is an image of a disk, it must be burned to a disk to be usable. You can not use it as a HDD install system.
You do not give a location on the planet, do you have access to a news agent, magazine shop? Here in Australia, we have a number of monthly computing magazines, most of which carry a cover disk full of software. Usually, there is at least one version of the Linux OS, in a freely installable format included on the cover disk. Maybe there is something similar in your part of the world. My advice would be to obtain a newer release of the OS. A word of warning, it may take a little while to find the right "flavour" of Linux to suit your needs. The great beauty of Linux is its flexibility. That can also be the source of much frustration and hair pulling, at the start of your wonderfull new journey.
Do not panic, the kernel will do that for you. The only stupid question, is the one never asked.
Ask lots of questions, and you will get lots of answers. Some you might even understand.
Hope this clears some fog for you. Good luck.
registered Linux user 437639
registered Linux machine 77042