a question about usb booting

[mike]

Hi, I made a usb start disc that works fine, but maybe one of you have a answer to this problem.
   I have a hp laptop that does not show a option for booting from usb in the boot menu or in the boot order in bios. Yet when I removed the hard drive it did boot from usb which means the feature is there.
Does anyone know if there is a setting I have to change in bios to enable this feature? If so what is the setting? At first glance having the menu red to me I didn't hear any setting that sounded like it was for that purpose.
Thanks Mike.