Open Guardian Antivirus and make sure there is no proxy set up. Additionally, add the application to the firewall's exclusion list. You can do it from Start > Control Panel > System and security > Windows Firewall > Allow a program through the firewall. If it still doesn't work, access the official website and download the update package. The archive is approximately 583 MB. Save the GUAR2014.exe file to your computer and then run it. Follow the instructions and the antivirus should be updated with the latest definitions.