The uses of USB disks have already increased so much for installing windows and sometimes booting a system is also performed using USB disks. But as you know this is limited to only motherboard that supports booting from USB disks / drive by the system BIOS.
But what to do with motherboards that doesn’t support booting using USB Flash disks? If this is the situation also for you when you have a mother board not supporting booting from a USB drive then free boot manager PLoP will be the best solution for you. This simple boot manager can work with your existing bootloader in BIOS. This can be launched from any device i.e floppy or a CD drive. And once launched you can use menus provided to boot your PC with almost any device like USB, CD or even from a Network.
You can download it from the link here in a zip format and follow the instruction included in the archive or you can visit publisher site to find more info and version history. Hope this will solve your problem…..