I can open firefox 3.6 (Windows XP) by clicking on its icon without any problems. It is my default browser. However, when I click on an external link, for example a link in a document or an email, it should launch firefox and open to the correct page. Instead, I get an hourglass cursor that lasts for minutes at a time. I have to resort to ctrl-alt-delete to interrupt the (futile) process. Why won't firefox launch properly from external links??