Suggest you go to the website of your ethernet controller and download the latest driver
then uninstall the one currently on your machine and re-install the new one. That way you have at least the correct one for the hardware installed and if that doesn't work can you start to suspect the card itself. After installing the driver go to device manager and make sure it is working and does not have a yellow warning triangle next to it indicating there is still a problem.
Hope this is of some help.