Another popular Pop-up Blocker, this software is also designed solely for preventing pop-ups. It installs the following toolbar within the browser: 
To disable pop-up blocking, click on the arrow to the right of the badge and a menu will appear with a list of options:
Click on Disable PopUpCop. To turn the Pop-up Blocker back on, you go back in and recheck the entry to re-enable their Pop-up Blocker.