Go to Sony Support page, identify your laptop model, select your operating system and download the LAN Card driver from Drivers & Software section. After that, press Windows + R key combination, type devmgmt.msc and click OK. Expand the Network Adapters list, right-click on the Sony LAN Card device and select Uninstall. Follow the provided instructions and reboot your computer. After that, go again to Device Manager, right-click on Network Adapters and select Scan for hardware changes. Right-click the Sony device, press Update Driver Software option and click Browse my computer for driver software. Select the downloaded LAN Card driver and install it following the self-explained steps. This should fix the problem.