|Your router might be using it's firewall features to block port 80. Might be it is failing or the modem is failing. Guess an oddity with the ISP. |
Look up telnet port 80 and try that. If that fails you are pretty sure it is a port 80 deal and not a browser issue.
"Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10