We have many Dell Latitude E5420 in our company with Windows 7 but 2 of the laptops have problem with web browsing. All of a sudden all http traffic stops but https traffic and others network services continue to work. Have tried winsock reset catalog which works after a restart but once the laptop is shut down and started the problem starts again. Same issue with other browsers as well.
Even tried system restore but no luck.
Since the issue is only on a couple systems, I doubt that it is hardware related. You may need to contact Microsoft to have them review the configuration of the OS to ensure that there isn't anything blocking HTTP (via the firewall, policy, etc.)