We're working on a completely new installer, but it's still a while away. And there's no guarantee that whatever has gone wrong with the Windows installs / accounts won't go wrong with another installer. (It is affecting other software's installers as well, after all.)
The real issue is that something is breaking people's Windows installs / accounts in some way which makes Windows start telling the installer it's on a 32-bit OS.
The solutions listed in Problems installing Opus have worked for almost everyone. Please try those.