One of the more popular Pop-up Blockers available, this software is designed solely for preventing pop-ups. It will install an icon in the lower right corner of your Start Menu Toolbar.
The following icon is the Pop-up Blocker: 
To disable pop-up blocking, right-click on the icon and a pop-up menu will appear with a list of options:
Uncheck the option Block pop-up ad windows. To turn the Pop-up Blocker back on, you can go back in and recheck the entry to re-enable their Pop-up Blocker.