Pop-up Blocker

• All Web browsers come with a built-in pop-up blocker. This useful tool automatically prevents any new windows from opening without your permission. Your pop-up blocker should be turned on by default, but if it has been inadvertently disabled, you can switch it back on by opening up your browser's Settings menu. The exact location of your pop-up blocker controls vary depending on what browser software you are using.
  
  

Attack Websites

• Some websites use sneaky JavaScript codes to force pop-ups open. Though these websites have lost their effectiveness as pop-up blockers have improved, the risk is still out there. These sites create a flurry of pop-up ads in the hopes that you will accidentally click within the window rather than closing it right away. This is usually done to transmit computer viruses or to redirect the user to a different site.
  
  

Browser Hijackers

• A browser hijacker is a virus that takes over your browser software. Unstoppable pop-up ads are a common symptom of browser hijackers, as well as automatically redirected URLs. One of the most telling signs of a browser hijacker infection is a reset homepage. If your browser is displaying any of these issues, shut down your browser immediately. Run a full system scan with your anti-virus software and follow any quarantine or removal instructions. You will likely need to reset your browser settings after the virus is removed.
  
  

Preventing Hijacking Attempts

• Browser hijackers often hitchhike along with unverified browser add-ons or within untrustworthy ads. Links within pop-up ads are also a common source of browser hijackers. To avoid hijackers, run regular anti-virus scans, install firewall software, avoid clicking on pop-up ads and only install add-ons from your browser's official add-on repository. Deleting email attachments from unknown contacts is also a wise precaution against browser hijackers and other forms of malware.