I tried to re-install Firefox after removing old version and then download the new installer. After clicking on the installer, all I have is an animated bar below which states "Downloading Firefox..." This continued for hour with no progress at all. I tried various ways to download the installer and still cannot get installation completed. This same system had been running very well with Firebox 42.0. When I received an update notice about 43.x, I tried to update it via the browser but failed. I thought something wrong with my browser so I uninstalled and tried to download the installer again. But all attempts failed. Anyone can help on this matter. I am running Windows 10 Pro with all latest updates.