I didn't use turboCNC however I know that TurboCNC work only under DOS but not with XP's comand prompt.
But there is a solution; you can boot your computer with a bootable floppy disk or CD. You can download free version of DOS from
http://www.freedos.org
I use Windows XP and Artsoft's MACH2. It work perfect with XP. you can download it at
http://www.artofcnc.ca