Booting from a USB keychain drive

[Devhux]

My laptop's BIOS has an option to boot from a USB keychain drive, and as such, I was curious on how I'd go about doing this with Windows XP. I'm guessing downloading a bootable ISO would be the way to do it, but how would I extract that to my pen drive?

[Hoser]

Start here:
http://www.bootdisk.info/

Just over halfway down the page, click on "USB Memory Drive Projects"

On the second page of the article is the information you need:
http://www.pcstats.com/articleview.cfm?articleid=1676&page=2

You format the USB drive with the "create a bootable system disk" option checked and then use the HP USB disk storage tool downloaded from here: http://h18007.www1.hp.com/support/files/hpcpqdt/us/download/20306.html