Unable to download software

So I managed all in one day erase all data from My Passport Essential SE and uninstall all software - totally uninentionally.  My PC (running Vista) seems to recognize it because when I plug it in, it asks to unlock the drive and the password is still the same as before.  I’m unable to download any software and the PC does not prompt me when I plug the drive in.  I only see the drive as empty folder under My Computer. help!

Download the ISO Image that contains the installer