In addition to the advice provided by the other poster, I would recommend against disabling your antivirus software to download a program.
Most modern antivirus software programs will allow legitimate programs to be downloaded without incident.
You would lose protection against malware and other threats if you disabled Norton.
Before disabling Norton, triple confirm that you are downloading a program from a legitimate source.
For instance, if you are trying to download the latest Google Chrome, make sure you do it directly from Google.ca/chrome. Not using a link sent to you by email, shown on a popup, Facebook, etc.