If you did not reinstall the driver, you may need to do so. The driver may be corrupted, infected, etc. and reinstalling it may solve the problem. If that doesn't help, try updating the driver with a similar version from those that come up in the update options. For example; the compatible drivers in my driver version options are: Realtek PCIe GBE family controller (Microsoft) and Realtek PCIe GBE family controller (Realtek) and any of this two drivers works the same, and if you remove the check mark from "Show compatible hardware" many other drivers in the list can be installed, some may work and some may not, but if you choose one that's very similar in brand, model but different version, it will certainly work the same.. just make a note of the driver that's installed before you start changing drivers so you can go back to it later when you have solved the cause.
You can also run the network adapter troubleshooter. Right click on the Network adapter icon in the taskbar and click Troubleshoot problems... whatever the cause it should diagnose it or fix it.
If that doesn't work, see if it's a hardware issue. If the Network adapter is integrated on the motherboard, you can try a PCIe/PCI Network or wireless adapter and if it works, the integrated adapter may be damaged. And if it's a PCIe/PCI adapter, specially if it's a wireless card, remove it and clean the slot with a can of compressed air, or a soft cotton cloth wrapped around a 1 or 10 cent coin and moistened with alcohol, and carefully sliding it through the slot.. instead of a coin, you can also use a piece of plastic cut out from any plastic bottle. Allow the alcohol to evaporate before reinstalling the card. That what I did on an old computer with a PCI nic card... the connection suddenly failed so I tried every fix I know and searched for solutions but nothing worked... I even moved the card to another two other slots and nothing worked. I then installed a second Windows on another partition to see if it was a windows issue and the same happened.. so I cleaned the PCI slots and that solved it. There wasn't any noticeable amount of dust or contaminant but a very small amount can hurt... that works for RAM as well.