VISTA and Chrome with McAfee Bitdefender
Chrome traffic may be blocked by Bitdefender. Check the McAfee Firewall settings in that case and reset the firewall rules.
To reset the firewall rules open BitDefender, switch it to Expert View from the Options button then go to the Firewall tab -> Programs and click on the ‘Reset Rules‘ button. Confirm when asked to reset the rules then restart the PC. The first time you run Chrome again, the Firewall should set a new rule and let the traffic flow.