How to find the right driver for "Unknown device" in Windows
Sometimes the following happens:
We don't know which device is "unknown" - it's not clear.
You can try to set the location of the driver as follows C:\Windows\System32\drivers (don't forget to tick Show compatible hardware), it might have some effect. But what if this doesn't work? Stay calm, because we have a solution even if everything fails:
1. In the context menu Unknown device, select Properties.
2. Go to the tab Details and select Hardware Ids from the drop down list.
3. There you can see lines like PCI\VEN_10EC&DEV_8168&SUBSYS_81681019&REV_01
4. Write down 4 characters after VEN_ and DEV_. In this case, 10EC and 8168, respectively.
5. Go to the website http://pcidatabase.com/ and input those characters into one of the fields Vendor Search or Device Search (preferred).
That's it, now search the driver for your OS and install it.