You can do this but will need to set up bootp software on your desktop.  With Windows, only Server versions have this - you'll need a third-party bootp software package.

http://www.keith-koep.com/service/doku.php/service/software/download/bootp

Unknown.  I have one external drive that I built with a 5.25" case and an NEC internal that won't work to boot any system I have - my Dell Inspiron, Thinkpad and my ASUS netbook, but it works fine as an external under WIndows.  The other external I built works fine to boot anything - probably has to do with the chipset on the controller board inside the external drive more than anything else (I can swap the two DVD drives without effect - the other one I have is an ASUS drive).

Much thanks for your timely reply. I am reviewing a third party solution but in the interim I would ask why is it that my HP external CD drive [USB connected] is recognized when windows in launched but when BIOS settings are modified to boot to that same CD first in order the boot process proceeds straight to the Windows Deskop as if the BIOS does not see connected devices.  The same is so for USB drives that are also recognized by windows but not in BIOS mode.  I would assume that the drivers are the same for both processes.  Much thanks in advance for an informed reply.

You can do this but will need to set up bootp software on your desktop. With Windows, only Server versions have this - you'll need a third-party bootp software package. http://www.keith-koep.com/service/doku.php/service/software/download/bootp