Download fails and corrupt files during download are usually symptoms of firewall rules at the desktop or at the firewall, virus scanner, proxies or group policies that monitor the network for downloads and with block or timeout.
Please make sure the download site is whitelisted.
An additional possibility that may work in some cases is that access is being constrained via your DNS.
In the Control Panel\Network and Internet\Network Connections
Select your network adapter" and change the Domain Name Server to Google ( 220.127.116.11, 18.104.22.168)
If you are unable to get this resolved in a timely manner we can provide a download link for the initial install (dropbox). However, in order to keep your software up to date you will need to whitelist the download sites.
Please let us know if we can be of assistance.