I get page not found when trying to download the setup file in IE and Firefox both.
http://download.comodo.com/cis/download/setups/CIS_Setup_3.8.65951.477_XP_Vista_x32.exe
Internet connection is fine. All firewalls, including Windows turned off. What’s the solution?
Welcome. 
That is an active link to the download. (See my screen shot). It could be your browser settings.
Did you try any other links, like these for example:
http://www.softpedia.com/get/Security/Security-Related/COMODO-Internet-Security.shtml
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