There are several essential components to computer security: a
knowledgeable and pro-active user, a properly configured firewall,
reliable and up-to-date antivirus software, and the prompt repair (via
patches, hotfixes, or service packs) of any known vulnerabilities.
The weak link in this "equation" is, of course, the computer user.
No software manufacturer can -- nor should they be expected to --
protect the computer user from him/herself.
To learn more about practicing "safe hex," start with these links: