I am currently running SW5.5 on "MacOS Catalina/VMware Fusion 11.5.0/Windows 2000" This has worked for nearly 20 years, but soon won't. I have to upgrade to VMware Fusion 12 because of the advent of Big Sur, and VMware Fusion 12 won't accept Windows 2000. The only purpose of this arrangement is to run Scientific Word (in the absence of a functional Apple version). The guest Windows machine is never allowed to contact the internet. My question is: Which version of Windows OS should I use to run SW5.5 and possibly the Windows version of SW6.0 ? There seems to be a lot of confusion between Windows 7 and 10. I would appreciate any advice from those who have kept up to date better than I have.