Getting Windows XP to Work

I've got a Windows XP boot-disk (legit), but my CD-Drive is so shot that it can't be read! My external disk-drive can see it easily--even autostarts it--when I'm on the computer (not trying to boot from a disk). I've gone into the setup-menu and set the boot-sequence to "onboard or USB disk-drive," but the USB disk-drive is never recognized. What should I do to get the external, USB drive to boot up the system?

Just get another CDR.  They're cheap and continue to be very useful for all manner of stuff that's released on CD.  In fact, get a CDRW since they'll probably be as affordable.