I'm using Windows Vista Business on my notebook. Yesterday all browsers (IE7, Firefox) stopped working. I did nothing. I didn't install or uninstall any software, didn't change any settings (but may be windows installed some updates).When I'm trying to access any website via HTTP (HTTPS works!) a browser resolves host name properly, connects to the server and is waiting for response. That's all I get. Network sniffer says that my computer sends and receives EMPTY http-packets (there are only IP and TCP headers and no data there!)Other network software is working well even when it is using http protocol (ICQ, jabber, weather widget, torrent) . I've already tried to:1. Disable windows firewall / windows defender2. Disable add-ons in IE3. Uninstall anti-virus software 4. Roll my system back (with system restore)5. Connect to the internet in a different way (via 3G)6. Disable all features in connection properties but "network client and TCP/IP v4 protocol)7. Rewrite network routes on my computer8. Connect to a webserver via telnet utility and communicate with it emulating http-client (that worked)9. Reset network connection.10. Stop all non-system running programsNothing helped. Can you advise something? I suppose the issue is connected with incapsulation of http protocol by the web-browsers (do IE and firefox use the same HTTP-client component? Is there any way to reinstall it?) How http access could be restricted?Thank you.

Hi kde, I would like to know the way the computer connects to the Internet. Meanwhile, please refer to the following steps for troubleshooting: 1. Boot into safe mode with networkingPlease browse websites using IE in safe mode with networking and check the result.Note If the following conditions are true, you cannot use safe mode with networking: You connect to the Internet by using a PPPoE connection. (Most DSL connections use PPPoE.) The PPPoE connection requires a username and a password. The computer is connected directly to a DSL modem. (If you connect to the Internet by using a router that is connected to a DSL modem, you can use safe mode with networking.) 2. Use SFC to check if the system file is missing or is corrupted. To do so, please refer to the KB article 929833 (http://support.microsoft.com/kb/929833). Hope it helps. Sincerely, Joson Zhou Microsoft Online Community Support

How http access could be restricted? http blocking can happen for various reasons. it can be initiated by a company admin to block the access to a certain website. Sometimes, other entities such as computer security products use Protocol Blockedhttps if they suspect a security problem with a certain site.