Vista Fax (in Ultimate) was running previously, with notifications when faxes arrived. Notifications suddenly stopped, but faxes arrived. I thought it might have lost its mind (!), did the OS programs uninstall/reboot/reinstall, checked Fax Service (automatic and on), retried Fax|Tools|Fax Settings, with and without admin privileges, and could not get Setting screen to launch. Also could not get Account to allow new account (or any account) to be setup.
Modem is a Vista-compatible Zoom, worked before, tests perfectly, picks up on a call, but software cannot find it.