You follow all the best security practices and heed all the warnings. You only visit web sites that are reputable or recommended by someone you trust. You never open unexpected attachments in email. You have a good anti-virus and anti-malware program installed. But somehow, you ended up with malware anyway. What happened?
This is a couple of months old, but it's still valid and useful information.
Scroll down to Editor's Corner to read the entire article.