When they say to change the BIOS, they mean you need to set the computer to try to boot off of a CD or USB device before trying to boot off of the hard drive. When you first turn on your computer, it will say ?Setup? or ?Menu? or ?Boot?, or something to that effect. Press the key indicated (it is almost always one of the function keys) and you will be able to change the order in which the computer will try to find an operating system.
When installing, you have to make sure that your BIOS are set to check the CD-ROM drive before the HDD. The computer will then boot directly from the CD into a setup environment; Windows will not be given the chance to load (which means if you do see the Windows logo, you need to change the BIOS).
Similarly, in order to run the Linux installation once it is installed, you will need to make sure that the BIOS are set so your computer will try to boot off of any USB devices (like your external HDD) before it tries to boot off of the hard drive. Some older computers may not have this option, but I believe there are ways around this problem using a boot floppy.
I have never installed Linux on an external hard drive before (although it is something I am considering), so I don?t know the specifics. This is where Google is your friend; you should be able to find instructions for your particular distro.
All that being said, I would encourage you to get a Linux book and read it before you try installing. It will walk you through a regular hard disk install, and coupled with the directions you find on Google you should be able to figure it out. Also, simply configuring and using Linux often requires more in depth knowledge than does Windows, so a good book will help you avoid some of the common pitfalls that newcomers make.
Good luck, and please let us know how it turns out.
How can I install Linux in My External HD in my XP machine. What is bios change means? XP is in my C: drive and E: is my external HD. Which will be easy for beginner(Linux)? I want to install from CD rom but I don't know how to do it without login in to my XP.