Ednpeach,
Presumably your BIOS doesn't support booting from an external usb-drive. But you should check that in the documentation, or in the BIOS itself.
But an external hard disk (even with usb2) is slower than an internal hard disk, so I don't suppose it's a good idea to do it, even if it's possible. Just use it for backup (a copy of data you don't want to lose) and transport. Or for data for a project you want to work on at different locations. Not for the OS or swap space.
Note that having data at only one place (be it a fixed hard disk, a removable hard disk, a diskette or a cd) is a sure recipe for losing it. Maybe tomorrow, maybe in 10 years, but losing it is certain.
Two years ago I gave a copy of my Windows 3.11 diskettes to my sister. When she needed them yesterday for install on another computer, she couldn't find them. That's just one example of what can go wrong. Well, I'm her backup for this.
Hope this helps,
Kees
Just out of curiosity...I'm thinking about extra storage and flexibility in the case of something ever going wrong with my computer. I've looked at internal and external hard drives. If I were to buy an external (usb), such as an Iomega 40gig, would it be possible to install Windows XP on it and use it as the main hard drive. New to all this stuff. Thanks for the help.

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