I am trying to install Norton Internet Security 2009 Add-on Pack, however, when I run the installation file I get the following message "A problem has occurred that needs your attention: The install file cannot be properly validated. Please try again. If you continue to receive this error message, you should run a Windows Update and then try again."
I am running Vista Premium. I have updated all there is to update with Windows Update, and I have tried this installation too many times to count and still get this error message. Help!