Vista: Internet Connection Issues (Browsers are fine)

Hi all, and thank you in advance for your responses.

I’m experiencing a few problems with Vista and with all applications (Except from Firefox) experiencing internet connection issues.

After uninstalling the IE8 update, IE started working again as normal, but Thunderbird and other net-dependant applications are still experiencing problems.

I’ve disabled TCP/IP v6, all ipconfig looks to be accurate, and am now at a loss as to what to try.

I’d be eternally grateful for your ideas and suggestions.