There is a continuing discussion about this here;
Have a read, see if anything there helps you.
Have you tried any different browsers?
Just got a new laptop, running Windows 7 64 bit. Installed Firefox 3.6.13 & set it as default. Also turned pop-up blocker off. Yet, for some reason, Firefox won't open certain hyperlinks. The most notable are links here on c-net for downloading software. I click the green download link, and it just reloads the page. Any help is appreciated.