Had a call this morning from a friend who couldn't browse after Firefox updated itself to 3.0.4. So after being stupid enough to get involved in this timewasting exercise it turned out only Firefox was failing - moreover it was able to resolve the website DNS but couldn't connect. Firefox settings looked fine - no proxies or anything strange. No IPV6 funnies. Cache and cookies were all cleared just in case. I discovered that turning off the firewall didn't fix it, reinstalling an older version of Firefox didn't fix it, winding back the system to a previous restore point didn't fix it, hitting it with a sledgehammer wouldn't have fixed it. My least favourite Anti-Virus software was installed - Norton Internet Security. So that was removed. Problem solved. I am really really p*ss*d off with Norton - yet again. Turning off the firewall had no effect. Adding Firefox explicitly to the program list had no effect.