Vista - DNS not reachable

Hi,

I had this problem only with one browser and now i have it with all my browsers. Whenever i try to enter my email or any other account with id and password i receive the error that the webpage cannot be displayed. The causes given are:

This problem can be caused by a variety of issues, including:

• <LI id=errorExpl2>Internet connectivity has been lost. <LI id=errorExpl3>The website is temporarily unavailable. <LI id=errorExpl4>The Domain Name Server (DNS) is not reachable.
• The Domain Name Server (DNS) does not have a listing for the website's domain.

This is only when i try to enter my accounts. Everything else works normal. I open the website, write my id and password and when i click to enter it gives me this error page.

How can i fix this?Plz help....