If you are not that knowledgeable, I would strongly suggest just reformatting the HD if you can. Amazingly enough, I am not sure there are any major distributions still geared towards installation using a boot disk. As a result, your best bet would actually be to step up to Gentoo, use their handbook, and install via a bootdisk in that method. Pretty much the main differences would be, instead of downloading and burning their boot disk/install CD, you would be using a floppy disk to boot your machine, and format, then chrooting into the machine's HD for the install and continuing from there like normal. Just make sure that your CD Rom drive is supported by the bootdisk you use, and mount the CD inside of the chroot.
I apologize for not being to much more helpful, but at this point in things, what you are doing is a more esoteric setup. I grew up on machines that didn't even have a 3.5 in floppy so please don't take that as offensive, it is just that they have largely been replaced by at least CD drives, if not DVD drives these days. As such, when you are starting to get into more esoteric setups, it is well worth the time, and the effort, to dig a bit deeper into Linux and do something along the lines of Gentoo, so you can start understanding exactly what doing lower level maintenence and troubleshooting is about.
In all actuality, once you get into the lower levels of Linux that most modern distributions try to make it so you don't need to, you will find that, even setting up more esoteric setups, is not to difficult. But until you really get into it and learn what some of the commands and techniques are (What a chroot is for instance) it can be extremely confusing, and very painful on my fingers to explain as you are essentially asking me to type out a good book there. Most of that book already exists in the form of the Gentoo installation handbook, which is why I reccomend that, and to post specific questions when you get to them. Read through it before you begin, print out a copy if you don't have a second computer availiable to read it online while doing the actual install, and ask questions before you begin if at all possible. You will likely screw up your first couple of installs, but don't get to discouraged, you will also likely learn a LOT about how to approach this exact situation in the future.