Recently a number of us had problems browsing using urls; the only way we could get to a site was using IP addresses.
SOLUTION:
Download and install Avast Antivirus (Free) run it and install Microsoft Service Pack 3
That eliminated the problem here.
Please, for those of you who have resolves for issues, BE SPECIFIC and don't take it for granted that everyone out there is as smart as you. Sometimes a small detail can save others many hours of confusion.
Hope this helps some of you. Have a great Thanksgiving and God Bless your lives.
Mike