Hello.
Nothing much is showing on your HijackThis log, can you run a new scan with AVG Anti-spyware and post the generated log into your next reply.
Meanwhile, here's a tip that I saw on the web. Try it, and if it does not help, reset it back:
Go to Start > Control Panel > Classic View and double-click Network and Internet connections. Next click Network Connections and right click your connection. Select properties. Under General tab make sure that the device listed is your correct modem. Click configure and make sure the Enable modem compression box is "unchecked". Click ok to save changes. Click ok to exit.