Before you try what artras said, could you test this:

  1. Right-Click the ‘a’ blue icon in the system tray.
  2. Run avast! antivirus.
  3. Right-Click the skin and choose Settings.
  4. Go to Update (Advanced) tab.
  5. Select the way you connect the Internet (dial up or DSL).
  6. Go to your browser and configure ‘Never dial a conection’ or ‘Use the default connection’ or anything you want.
  7. Boot.

Must work :-\