Runnig only and antivirus program will not protect you from malicious script inserted into webpages, links, or E-mails. Now days, many reputable sites are getting hacked and having malicious script inserted into them, without the knowledge of the WebSite owners. Many AV programs and spyware/malware programs will help to detect this type of script. But only if they know about them. This may sound like a PREVX advertisement, but PREVX is one of the only security programs that only allow 'known good programs' and files to run. Thus, not allowing the bad stuff to even get a foothold on your system.