Thanks. Sharing was the original goal across computers to my network drive but that got more complicated than seemed worth the trouble.
But "something" is causing great difficulties after the initial installation on only the Windows 7 of the 3 computers (XP, XP, Vista/Windows 7) network. Every attemt to build the system with a new package fails. I wondered if it was even possible there was something specific to the dual-(Windows)-boot causing it.
I felt the same that the isolation of the two OSs should be complete, but at this point I was looking for any possible conflict, even in the boot sector.
Thanks again.