The suggestion to get a live cd version of a LINUX distribution is a good one. for the last two months I've been suggesting the Ubuntu ditribution. Just make sure your system has a free partition and is connected to the LAN and the Internet (through your gateway is OK), then boot the system from the CD.
Ubuntu has two CD formats: The live CD runs from your cd drive and requires no installation. Running this will let you know if Ubuntu will find all the right components for your system. (This should be no problem. Ubuntu was the only disto that found ALL of the component drivers for mY Toshiba laptop, including my wireless interface.) Once you get a chance to play around with it, go ahead and install the distro from the install CD.
Ubuntu is letting people order CD's from their site, but it's not necessary. A boxed set is not necessary. Using any windows system, downloat the ISO files from the Ubuntu site. I also downloaded a great little utility called isorecorder. Once you have the ISO files dowloaded, if you have isorecorder installed you can right click on the file and the top menu item will burn the ISO to your CD. (Just copying the ISO to your CD will NOT produce a bootable disk.)
One last thing: Ubuntu installs a pretty hefty version of LINUX, but the Synaptic utility will probably help you locate many other utilities and some deprecated older utilities like rc and dd that may not be installed at first installation.
FYI, the Ubuntu distro is based on the Debian distro, and once you get it installed you should go to the website to find the technical articles for installing multimedia codecs and utilities for Mozilla.
I hope this helps.