All Windows 7 PC's (400) across our domain have recently started displaying a yellow warning triangle in the botton right of the screen with a message saying 'No Internet Access'. The machines can access the internet absolutely fine.
I have rebooted PC's, run repairs on the network adapter, Disabled and Enabled the connection. Deleted and re-installed the network card and cleared out Proxy Settings and so far only one thing seems to resolved it. I can get the warning to disappear on my PC by conneting up to an FTP site (using FireFTP). When I disconnect again the warning stays away.
As far as I know nothing has changed on our switches or ISA Server and we have the desktop firewalls disabled and run McAfee Enterprise 8.8
Does anyone have any ideas why this might be occuring and how I might resolve this for my other users ?