I just upgraded my laptop from Vista to 7 and I can't access MOST websites. I can get to Yahoo, My.Yahoo.com Google, facebook, and a few others (however subpages - like yahoo news articles don't work), but if I try to go to my website, or 100 other sites I get "Could not find". Doesn't matter what browser I'm using, and my other computers on the same network are NOT having any issues at all. I've made sure all firewalls are OFF and (if possible) uninstalled, tried refreshing my IP, DNS, and other network settings, I've run malware and virus hunting software, checked the individual browser security settings, checked windows security setting - even changed them to the minimum. Nothing is working. I can connect via my network to the other computers on my network, and other internet calls by the computer (ie. programs that check for updates) works. I'm stumped, and none of the fixes on the internet have helped either.
Have you tried creating a new clean user and try from there? maybe it can be related to a corrupted windows user profile.