Ultimate Boot CD

As far as I know, there is no generic method for doing so i.e. it is OS specific.

I know of some Linux distros that supply a floppy or CD boot image to let you boot into a USB memory stick or HDD. That's about it.

booting from USB stick is different from USB CDROM...I have a mobo that's a few years old and it supports booting from usb cdrom, automatically even if there's no other boot drive found.

USB flash drives have to be formatted in FAT16 like a floppy to be used as boot disks