Heyo, I'm just here to say thanks for this thread. I was in the same situation as well.
One day, on my parent's laptop, Windows found a trojan. I decided to download AVG free, scanned, and got rid of some additional trojans. Afterwards, I couldn't browse the internet with Firefox, Chrome, or IE.
I checked every settings listed:
- Proxy Settings
- DNS Settings
- Repairing all connections.
- Releasing Renewing IPs
- Rebbooting Routers/Modems
I could ping websites just fine (www.google.com); However, I couldn't use any applications to connect.
I disabled firewalls, uninstalled all anti-virus/malware programs and checked all processes that were running and all seemed normal.
I tried browsing in safemode, but still couldn't connect.
Then I tried "netsh winsock reset catalog" and bingo-bango!
Thanks again!