DavidR
7
If were talking malicious code, then yes avast may be able to help in that regard but nothing is perfect as ross mentions.
Before using ant so called anti-application, be it anti-virus/spyware/spam, etc. then you should first do some research and see what the internet brings up on that, there are many rogue programs out there one good resource is http://www.spywarewarrior.com/rogue_anti-spyware.htm.
The other extensions I mentioned before (DrWeb Link checker, there are others and SiteAdvisor) are also ones that you should try before clicking on a link in a web page.