Hi Popo,
it seems there is something on your PC that is blocking the connection between Firefox and WebShield. I can see WebShield is listening on its port.
AvastSvc.exe: localport=12080, State=LISTENING
Those FireFox.exe connections with SYN_SENT are connections attempt to WebShield, which is also perfectly normal. But here, webshield should response and create the connection between Firefox. Which apparently does not happen at your setup. Either there is something blocking it (a firewall?) or WebShield is somehow !stuck!
If you terminate WebShield in the GUI, does the listening 12080 port wanishes? (if WebShield is stuck, it usually does not responds to stop requests and the port remains opened/in listening state even when the provider was requested to stop).
Thanks.
L.