Hey, so I've actually had this problem a long time ago with Windows XP... Don't remember how I fixed it but I think it was just a full reformat.
Windows 7 worked before, internet, everything was fine - until yesterday when my internet crashed (in my entire house). I have a separate computer up (the original one that had this issue) right next to it. My entire house went down for internet for a long time. I went to sleep, woke up the next day - internet is working on Windows XP. Great! It's back. Windows 7 doesn't have internet anymore. Still connected to the home network, just says no internet access. They are both connected to the same switch by ethernet cable, which then runs to the router out in the living room.
Weird thing is, I still have SOME internet capabilities. For instance, Ventrilo and UltimateBet both still work fine, have full internet capabilities. (Ultimate bet the ads don't load correctly, page load error comes up). When I start up mozilla firefox, IE, any other game, etc, they almost don't even try to connect.
I tried /release /renew, uninstalling the network card, restarting, winsockxp fix.... Not sure what else to try. Thanks guys.