Yes, ad blockers, such as Adblock Ultimate or Total Adblock can block viruses. Because ad blockers prevent certain page elements from loading, this can also prevent infected scripts from load on web pages or prevent pop-ups with malicious phishing links from showing up on your screen. That said, ad blockers are not an effective antivirus tool. If you need an actual antivirus solution that also has an ad blocker, consider Total Adblock.