Internet/computer question

[Onlooker]

For some reason, some sites are coming up as blank pages. In other words, I go to the site and there's nothing there, only its name in the address bar and a white window. This has happened on a shopping site, a japanese travel site, and a site that contained an essay.

I ran a virus scan, found nothing. My firewall was on as far as I know, but I had to download a fix in order to view its settings. (I found that odd; I think I've viewed its settings in the past.)

Do you have any idea of what might be causing the problem I describe.