IE, fire fox not working

I am unable to browse using IE8 or fire fox the error message is internet explorer cannot display the webpage

1. connection is good able to browse with MS outlook.
2. all setting are ok , ( proxy setting unchecked, etc)
3. unable to update virus software.
4. messenger and gtalk is working.
5. uninstalled and reinstalled IE8 and fire fox - still having the same problem
6. uninstalled and reinstalled virless usb software problem not solved
7. reset ie setting did not give any result

please help me to solve this problem, i searching internet more that a week to sovle this problem pl help me to solve this problem