Pop-up Blockers: can also interfere with other, legitimate applications.
We have found that Pop-up Blockers are causing issues on the order page, They stop you from entering the selected form of delivery IE: Royal mail, UPS, and others,
This must be set to "allow" whitelisting functionality, the pages in the checkout process to render,
Please see "Alternative browsers" Firefox, Safari and Opera are similar to the browser toolbars in that they block pop-ups that are launched automatically but don’t block anything the user initiates. However, unlike the browser toolbars, the alternative browsers don’t all have whitelisting functionality, so users may have to turn the blockers off completely if they want to see automatic popups from specific sites.
Google toolbar Click the pop-up blocker button on the Google toolbar to allow pop-ups from the current site. Hovering over the button provides tooltips with instructions.
Yahoo toolbar Select pop-up blocker dropdown menu, click “Always Allow Pop-ups From...” to display a list of sites where pop-ups have been blocked. Select site and click “Allow” to add site to whitelist. Note that you can’t proactively whitelist a site
Yahoo must have blocked a pop-up from that site before you can whitelist it.
MSN toolbar Select pop-up blocker dropdown menu, click “Allow Pop-ups For This Site” to whitelist the current site. Click “Pop-up Guard Settings” to manually add URLs to the whitelist or turn on “Allow pop-ups from intranet sites.” XP SP2 Add site to Trusted domain in IE Security settings. Select Tools | Internet Options | Security tab, then choose Trusted sites and click Sites button to add URLs.