I must be thick because I can't seem to understand this..

Here is what I have:
An existing WinXP computer with two hard drives, each with a single NTFS partition.
A third hard drive connected via USB - works fine with XP. Has an NTFS and ext2 partition.

Here is what I'd like to do:
I'd like to give Linux a try on this computer but without impacting the existing system (i.e the two internal harddrives). The goal was/is to install linux on the USB drive and boot to it from external media (CD or Floppy). I'd prefer not to mess with LILO or GRUB on any of the drives hence the thought to boot from CD when I want to run Linux. I may make it more permanent when I get some run time on it.

Here is what I have done to date:
I installed Fedora Core 1 on the USB drive from CD. I did it by installing in "expert" mode so it recognized the USB drive. I did not create a boot disk at the time of installtion (probably a big mistake).

Questions:
I'm told I can boot fc1 (not to install but to run) from the installation CD but I can't for the life of me seem to understand what commands to issue at the "boot:" prompt. ???
If the installation CD is not the best boot media, how do I create a boot disk (or CD) that does what it needs to do to point to the fc1 installation on the USB drive?

I've read the "HowTos" and still don't get it.

Any help would be greatly appreciated.

Thanks in advance.

Frank M.