Thanks. I see from those links that others have gone down the same road I'm on now.
My problem doesn't appear to be related to the Suunto Dive Manager software and hardware; rather, Windows 7 is not recognizing my USB-to-serial converter, a U232-P9. I downloaded an updated driver installer here: Welcome to Prolific
and ran it. However, when I plug in the USB-to-serial converter, Windows 7's Device Manager shows it as an "Unknown Device" with no driver installed.
Is there a place under Windows 7 where I can direct it to look for the updated driver I just installed? I pointed it to the unzipped driver installer folder, but Windows 7 doesn't find a driver there.