(sigh)
OK; I uninstalled AHIII, and will run AH2261.exe, which is the latest full install exe on my backup media; this will install AHII. Hopefully I don't have to update it to the last version of AHII, as that involves running about 10-15 update exes.
EDIT: In the end, I just installed 2261, copied verbatim my "settings" folder from the last version of AHII, and AHIII imported the settings.
MH