There are many programs and tools on the computer that can cause website to be blocked. Unless your computer is detecting a bad virus, it is not likely that the anti-virus software is not doing the blocking. Windows has but in security features that allow you to change the level is security protection being used. Firewalls also block websites based on what it is set to allow and disallow.
"The McAfee virus protection software is as effective as other major virus protection software brands, and offers many typical features, such as firewall protection, e-mail filtering, and website security checks for safe internet browsing."
Uninstall the virus protection. (Some are notoriously difficult to get rid of).
Delete all temporary files in Internet Explorer or what every browser you are using. Then do a complete virus scan on the computer.
A computer virus, probably.
anti-virus
Anti-virus software can be purchased in traditional electronics stores such as Best Buy or even Walmart. Additionally, anti-virus software is available for download from the software company's website.
We need virus protection software to safe your PC from Online and Offline threats.
One can find reviews on virus protection programs on the official websites of the virus protection program providers. In addition, one can find reviews on blogspots.
Try Malwarebytes Anti-Malware
Pop-Ups on computers can be caused by individual websites or viruses on your computer. To block them, download a computer Anti-Virus & Protection Program that enables pop-up blocking.
Windows Live OneCare has Anti-virus, firewall, spyware protection
Your computer can get a virus simply by going to the wrong website or opening the wrong email. People will send you emails with viruses in them and when you read them your computer gets infected. The best way to protect your computer from viruses is to have anit virus software.