I am actually facing the same issues as you have, on a laptop, running vista (32-bit) with zonealarm and avast free edition.After a while, when I try opening a webpage in my browser, I get "website found, waiting for reply" in the left below corner , and the browser isnt going anywhere.When I started stopping the avast services (after killing nearly every other service and firewalls),I noticed that the problem got resolved when I stopped the avast webshield service. A temporary workaround for me was to install a tool named fiddler,a browser debugger, which allows you to launch an iexplorer from within the tool, and this works without issues, even when at the same time iexplorer does not work directly.
best regards,
G.