While connected to a public wireless network at a hotel, my laptop lost its ability to browse websites via HTTP. The problem persisted when I returned home using my private wireless network. However, I noticed I can browse sites via HTTPS and FTP. I can even ping external websites in Command Prompt. (For example, using the command “ping google.com”, I receive IP address replies.) Windows appears to be downloading regular updates as well. This could be a setting I have unknowingly disabled.
Unsuccessful attempts to resolve the issue include:
--Sweeping my system for malware with Trend Micro and Malwarebytes’;
--Connecting to the network through an Ethernet port;
--Temporarily disabling my firewall;
--Temporarily disabling my antivirus software;
--And running Network Diagnostics for Windows XP.
All were no help.
I’m stumped. Any ideas would be greatly appreciated. Thanks!
Solved this. Thought I'd share in case anyone experiences this problem.
I could not access the Internet using HTTP because Trend Micro Antivirus was blocking port 80, which is most often used by HTTP. This is why I could not browse sites using HTTP while HTTPS and FTP, which use other ports, worked without issue.
To correct the problem, I uninstalled Trend Micro Antivirus and reinstalled AVG Antivirus. This lifted the block on port 80, allowing me to browse sites using HTTP. Interesting that uninstalling the software corrected the problem while temporally disabling Trend Micro, which I tried earlier, did nothing. I chose not to reinstall Trend Micro because AVG Antivirus is free and I did not have my Trend Micro product key at the time.
I have used Trend Micro Antivirus for little more than one year. Never had an issue like this. It came on suddenly. I wonder if Trend Micro could have issued a buggy update in October 2010 that caused port 80 to be blocked.