Pop-under advertisements that are initiated by websites that you visit can be blocked from your web browser. Changing the settings in your web browser to block pop-under ads will also prevent pop-up ads from displaying. Pop-unders can only be blocked using your web browser if they are opened by web sites that you visit. Pop-under advertisements that pop as a result of adware installed on your computer must be removed from the system using an adware or spyware removal program.
Open the Google Chrome browser from your Windows desktop. Click the blue wrench-shaped icon in the upper right-hand corner of the browser.
Choose "Options" from the menu that appears underneath the wrench icon. Click the "Under the Hood" label in the Google Chrome Options window.
Click "Content settings..." underneath the "Privacy" heading. Click the "Pop-ups" tab.
Left click the bubble next to the text that reads, "Do not allow any site to show pop-ups." Click "Close." Pop-under and pop-up ads will now be blocked in Chrome.
Launch Mozilla Firefox from your computer's desktop or "Start" menu. Left click on the "Tools" button located on the menu bar towards the top of the Firefox window.
Select "Options" from the drop-down menu that appears. Left click on the "Content" icon near the top of the window that opens.
Click the empty box next to "Block Popup Windows" to place a check mark in it. Click "OK" at the bottom of the "Options" window. Restart Firefox by closing the browser and opening it back up. Pop-up and pop-under ads will now be blocked automatically.
Start the Safari browser from your computer's desktop. Click "Safari" in the left corner of the menu bar (next to the Apple icon).
Move your cursor to highlight the "Block Pop-Up Windows" option in the menu. Click on "Block Pop-Up Windows" to place a check mark next to the text.
Restart the Safari browser. Both pop-under and pop-up ads will now be blocked by Safari.
Open Internet Explorer from the Windows desktop. Click on the button labelled "Tools" underneath the address bar.
Scroll over the "Pop-up Blocker" button to highlight it in the menu that appears. Left click "Turn on Pop-up Blocker" in the small menu that displays to the right.
Click "Yes" when the prompt asking if you are sure that you would like to turn on the Internet Explorer Pop-up Blocker appears. Internet Explorer will now block pop-ups and pop-unders initiated by websites.
Double click on the Opera icon on your desktop to open the browser. Single click on the "Tools" button located on the Opera menu bar.
Select "Quick preferences" in the window that is opened. Choose "Block all pop-ups" from the list of available options.
Click the "OK" button to save the pop-up blocker settings. Close any Opera windows that are open on your computer. Reopen Opera and the settings blocking pop-unders and pop-ups will take effect.
The pop-up blocking feature within web browsers cannot block pop-unders or pop-ups that display as a result of adware.