Windows 2000 loses internet connection (sort of)

[jm0ut]

Something very weird is happening to me. Sometimes when I am surfing the web, out of the blue it decides its not going to let access anymore webpages. My internet connection is not lost because I can still ping and use AIM. So I have to log out and log back in to get the browser to work again. I am using windows 2000. Any thoughts??